Android总结

时间:2024.3.27

Android总结

第一步:

Android(1) - 在 Windows 下搭建 Android 开发环境,以及 Hello World 程序

搭建 Android 的开发环境,以及写一个简单的示例程序

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在 Windows 下搭建 Android 开发环境 Android 项目的目录结构说明 写一个简单的 Hello World 程序

一、在 Windows 下搭建 Android 开发环境

1、安装 JDK (Java Development Kit)

/jdk6/

2、安装 Android SDK

/sdk

3、安装 Eclipse

/

4、打开 Eclipse ,并安装其 Android 插件(ADT)

打开菜单 "Help" -> "Install New Software",在 "Availabe Software" 中加入地址

http://dl-/android/eclipse/ ,然后安装 ADT(Android Development Tools)

5、新建 Android 项目

"New" -> Android Project,Project Name - 项目名称;Build Target - 编译项目的 SDK 版本;Application name - 程序名称;Package name - 包名;Min SDK Version - 程序所支持的最低 SDK 版本代号(2 对应 1.1,3 对应 1.5,4 对应 1.6)

6、运行 Android 项目

打开菜单 "Run" -> "Run Configurations" -> New launch configuration,设置启动项目名称,在 Android 选项卡中选择启动项目,在 Target 选项卡中设置模拟器

7、创建/使用模拟 SD 卡

创建 SD 卡,运行类似如下命令:mksdcard -l sdcard 512M d:\android\sdcard.img

模拟器中使用 SD 卡,在项目配置的 Target 选项卡的 "Additional Emulator Command Line Options" 框中输入类似如下参数:-sdcard d:\android\sdcard.img

8、配置模拟器

运行类似如下命令:android create avd --name android15 --target 2。或者直接在菜单 "Window" -> "Android AVD Manager" 中配置模拟器

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9、浏览模拟 SD 卡中的内容

调试程序,在 DDMS 中选择 "File Explorer" ,在其中的 sdcard 目录下就是模拟 SD 卡中的内容

10、查看日志 LogCat

Window -> Show View -> Other -> Android -> LogCat

11、在模拟器中安装/卸载 apk

安装 apk 运行类似如下命令:adb install name.apk;卸载 apk 运行类似如下命令:adb uninstall packagename(注:这里的参数是需要卸载的包名)

12、反编译 Android 程序

解压 apk 文件,取出其中的 classes.dex 文件,运行类似如下命令:dexdump.exe -d classes.dex > dump.txt(其意思是将 classes.dex dump 出来,并将反编译后的代码保存到指定的文本文件中)

13、人品不好是出现的某些错误的解决办法

如果出现类似如下的错误等

no classfiles specified

Conversion to Dalvik format failed with error 1

解决办法:Project -> Clean

出现 Android SDK Content Loader 60% (一直卡在 60%)

解决办法:Project -> 去掉 Build Automatically 前面的勾

14、查看 SDK 源代码

先想办法搞到源代码,如这个地址 /android.asp ,然后将其解压到 SDK 根路径下的 sources 文件夹内即可

二、Android 项目的目录结构

1、src - 用于放置源程序

2、gen - 自动生成 R.java 文件,用于引用资源文件(即 res 目录下的数据)

3、assets - 用于放置原始文件,Android 不会对此目录下的文件做任何处理,这是其与 res 目录不同的地方

4、res/drawable - 用于放置图片之类的资源;res/layout - 用于放置布局用的 xml 文件;res/values - 用于放置一些常量数据

5、AndroidManifest.xml - Android 程序的清单文件,相当于配置文件,配置应用程序名称、图标、Activity、Service、Receiver等

三、Hello World 程序

1、res/layout/main.xml 代码

<?xml version="1.0" encoding="utf-8"?>

<!--

设置 ID 的方式:ID前加前缀,@+id/

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引用资源文件内字符串资源的方式:指定的资源名称前加前缀,@string/

-->

<LinearLayout xmlns:android="/apk/res/android" android:orientation="vertical"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:id="@+id/layout"

>

<TextView

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="@string/hello"

/>

<TextView

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:id="@+id/txt"

/>

</LinearLayout>

2、res/values/strings.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<resources>

<string name="hello">layout 直接调用 values 中的字符串</string>

<string name="hello2">编程方式调用 values 中的字符串</string>

<string name="app_name">webabcd_hello</string>

</resources>

3、res/drawable 目录下放置一个名为 icon.png 的图片文件

4、AndroidManifest.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="/apk/res/android" package="com.webabcd.hello"

android:versionCode="1"

android:versionName="1.0">

<application android:icon="@drawable/icon" android:label="@string/app_name">

<activity android:name=".Main"

android:label="@string/app_name">

<intent-filter>

<action android:name="android.intent.action.MAIN" />

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<category android:name="android.intent.category.LAUNCHER" /> </intent-filter>

</activity>

</application>

<uses-sdk android:minSdkVersion="3" />

</manifest>

5、Main.java 代码

package com.webabcd.hello;

import android.app.Activity;

import android.os.Bundle;

import android.widget.LinearLayout;

import android.widget.TextView;

public class Main extends Activity {

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

// 将指定的布局文件作为 Activity 所显示的内容

setContentView(R.layout.main);

// 动态地在指定的容器控件上添加新的控件

TextView txt = new TextView(this);

txt.setText("动态添加控件");

// setContentView(txt);

((LinearLayout)this.findViewById(R.id.layout)).addView(txt);

// 引用资源文件内的内容作为输出内容

TextView txt1 = (TextView)this.findViewById(R.id.txt);

txt1.setText(this.getString(R.string.hello2));

}

}

Android(2) - 布局(Layout)和菜单(Menu)

介绍

在 Android 中各种布局的应用,以及菜单效果的实现

? 各种布局方式的应用,FrameLayout, LinearLayout, TableLayout, AbsoluteLayout, RelativeLayout

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为指定元素配置上下文菜单,为应用程序配置选项菜单,以及多级菜单的实现

1、各种布局方式的演示

res/layout/main.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<!--

layout_width - 宽。fill_parent: 宽度跟着父元素走;wrap_content: 宽度跟着本身的内容走;直接指定一个 px 值来设置宽

layout_height - 高。fill_parent: 高度跟着父元素走;wrap_content: 高度跟着本身的内容走;直接指定一个 px 值来设置高

-->

<!--

LinearLayout - 线形布局。

orientation - 容器内元素的排列方式。vertical: 子元素们垂直排列;horizontal: 子元素们水平排列

gravity - 内容的排列形式。常用的有 top, bottom, left, right, center 等,详见文档

-->

<LinearLayout xmlns:android="/apk/res/android" android:orientation="vertical" android:gravity="right"

android:layout_width="fill_parent" android:layout_height="fill_parent">

<!--

FrameLayout - 层叠式布局。以左上角为起点,将 FrameLayout 内的元素一层覆盖一层地显示

-->

<FrameLayout android:layout_height="wrap_content"

android:layout_width="fill_parent">

<TextView android:layout_width="wrap_content"

android:layout_height="wrap_content" android:text="FrameLayout"> </TextView>

<TextView android:layout_width="wrap_content"

android:layout_height="wrap_content" android:text="Frame Layout">

</TextView>

</FrameLayout>

<TextView android:layout_width="wrap_content"

android:layout_height="wrap_content" android:text="@string/hello" />

<!--

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TableLayout - 表格式布局。

TableRow - 表格内的行,行内每一个元素算作一列

collapseColumns - 设置 TableLayout 内的 TableRow 中需要隐藏的列的列索引,多个用“,”隔开

stretchColumns - 设置 TableLayout 内的 TableRow 中需要拉伸(该列会拉伸到所有可用空间)的列的列索引,多个用“,”隔开

shrinkColumns - 设置 TableLayout 内的 TableRow 中需要收缩(为了使其他列不会被挤到屏幕外,此列会自动收缩)的列的列索引,多个用“,”隔开

-->

<TableLayout android:id="@+id/TableLayout01"

android:layout_width="fill_parent" android:layout_height="wrap_content"

android:collapseColumns="1">

<TableRow android:id="@+id/TableRow01" android:layout_width="fill_parent"

android:layout_height="wrap_content">

<TextView android:layout_width="wrap_content"

android:layout_weight="1" android:layout_height="wrap_content"

android:text="行1列1" />

<TextView android:layout_width="wrap_content"

android:layout_weight="1" android:layout_height="wrap_content"

android:text="行1列2" />

<TextView android:layout_width="wrap_content"

android:layout_weight="1" android:layout_height="wrap_content"

android:text="行1列3" />

</TableRow>

<TableRow android:id="@+id/TableRow01" android:layout_width="wrap_content"

android:layout_height="wrap_content">

<TextView android:layout_width="wrap_content"

android:layout_height="wrap_content" android:text="行2列1" />

</TableRow>

</TableLayout>

<!--

AbsoluteLayout - 绝对定位布局。

layout_x - x 坐标。以左上角为顶点

layout_y - y 坐标。以左上角为顶点

-->

<AbsoluteLayout android:layout_height="wrap_content"

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android:layout_width="fill_parent">

<TextView android:layout_width="wrap_content"

android:layout_height="wrap_content" android:text="AbsoluteLayout"

android:layout_x="100px"

android:layout_y="100px" />

</AbsoluteLayout>

<!-- RelativeLayout - 相对定位布局。

layout_centerInParent - 将当前元素放置到其容器内的水平方向和垂直方向的中央位置(类似的属性有 :layout_centerHorizontal, layout_alignParentLeft 等) layout_marginLeft - 设置当前元素相对于其容器的左侧边缘的距离

layout_below - 放置当前元素到指定的元素的下面

layout_alignRight - 当前元素与指定的元素右对齐

-->

<RelativeLayout android:id="@+id/RelativeLayout01"

android:layout_width="fill_parent" android:layout_height="fill_parent">

<TextView android:layout_width="wrap_content" android:id="@+id/abc" android:layout_height="wrap_content" android:text="centerInParent=true"

android:layout_centerInParent="true" />

<TextView android:layout_width="wrap_content"

android:layout_height="wrap_content" android:text="marginLeft=20px"

android:layout_marginLeft="20px" />

<TextView android:layout_width="wrap_content"

android:layout_height="wrap_content" android:text="xxx"

android:layout_below="@id/abc" android:layout_alignRight="@id/abc" />

</RelativeLayout>

</LinearLayout>

res/values/strings.xml

<?xml version="1.0" encoding="utf-8"?>

<resources>

<string name="hello">Hello Layout</string>

<string name="app_name">webabcd_layout</string>

</resources>

Main.java

代码

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package com.webabcd.layout;

import android.app.Activity;

import android.os.Bundle;

public class Main extends Activity {

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

}

}

2、上下文菜单,选项菜单,子菜单

res/layout/main.xml 代码

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<TextView android:id="@+id/txt1" android:layout_width="fill_parent"

android:layout_height="wrap_content" android:text="@string/hello_contextMenu" />

<TextView android:id="@+id/txt2" android:layout_width="fill_parent"

android:layout_height="wrap_content" android:text="@string/hello_subMenu" /> </LinearLayout>

res/values/strings.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<resources>

<string name="hello_contextMenu">Hello Context Menu</string>

<string name="hello_subMenu">Hello Context Sub Menu</string>

<string name="app_name">webabcd_menu</string>

</resources>

Main.java

代码

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package com.webabcd.menu;

import android.app.Activity;

import android.os.Bundle;

import android.view.ContextMenu;

import android.view.Menu;

import android.view.MenuItem;

import android.view.SubMenu;

import android.view.View;

import android.view.ContextMenu.ContextMenuInfo;

import android.widget.TextView;

import android.widget.Toast;

// 演示两种菜单的实现方式:上下文菜单(通过在某元素上长按,来呼出菜单)和选项菜单(通过按手机上的菜单按钮,来呼出菜单)

public class Main extends Activity {

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

// 为 R.id.txt1 注册一个上下文菜单(在此 TextView 上长按,则会呼出上下文菜单) // 具体呼出的菜单内容需要重写 onCreateContextMenu 来创建

TextView txt1 = (TextView) this.findViewById(R.id.txt1);

this.registerForContextMenu(txt1);

// 为 R.id.txt2 注册一个上下文菜单

TextView txt2 = (TextView) this.findViewById(R.id.txt2);

this.registerForContextMenu(txt2);

}

// 重写 onCreateContextMenu 用以创建上下文菜单

// 重写 onContextItemSelected 用以响应上下文菜单

@Override

public void onCreateContextMenu(ContextMenu menu, View v,

ContextMenuInfo menuInfo) {

super.onCreateContextMenu(menu, v, menuInfo);

// 创建 R.id.txt1 的上下文菜单

if (v == (TextView) this.findViewById(R.id.txt1)) {

// ContextMenu.setIcon() - 设置菜单的图标

// ContextMenu.setHeaderTitle() - 设置菜单的标题

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menu.setHeaderIcon(R.drawable.icon01);

menu.setHeaderTitle("我是菜单");

// 用 ContextMenu.add() 来增加菜单项,返回值为 MenuItem

// 第一个参数:组ID

// 第二个参数:菜单项ID

// 第三个参数:顺序号

// 第四个参数:菜单项上显示的内容

menu.add(1, 0, 0, "菜单1");

// MenuItem - 新增菜单项后的返回类型,针对菜单项的其他设置在此对象上操作 menu.add(1, 1, 1, "菜单2").setCheckable(true);

}

// 创建 R.id.txt2 的上下文菜单(多级上下文菜单)

else if (v == (TextView) this.findViewById(R.id.txt2)) {

// ContextMenu.addSubMenu("菜单名称") - 用来添加子菜单。子菜单其实就是一个特殊的菜单

SubMenu sub = menu.addSubMenu("父菜单1");

sub.setIcon(R.drawable.icon01);

sub.add(0, 0, 0, "菜单1");

sub.add(0, 1, 1, "菜单2");

sub.setGroupCheckable(1, true, true);

SubMenu sub2 = menu.addSubMenu("父菜单2");

sub2.setIcon(R.drawable.icon01);

sub2.add(1, 0, 0, "菜单3");

sub2.add(1, 1, 1, "菜单4");

sub2.setGroupCheckable(1, true, false);

}

}

// 重写 onCreateOptionsMenu 用以创建选项菜单

@Override

public boolean onCreateOptionsMenu(Menu menu) {

MenuItem menuItem = menu.add(0, 0, 0, "菜单11xxxxxxxxxxxx111111");

// MenuItem.setIcon() - 设置菜单项的图标

// MenuItem.setTitleCondensed() - 菜单的简标题,如果指定了简标题的话,菜单项上的标题将会以此简标题为准

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// MenuItem.setAlphabeticShortcut() - 设置选中此菜单项的快捷键

// 注:菜单项超过 6 个的话,第 6 个菜单将会变为 More 菜单,多余的菜单会在单击 More 菜单之后显示出来

menuItem.setIcon(R.drawable.icon01);

menuItem.setTitleCondensed("菜单1");

menuItem.setAlphabeticShortcut('a');

menu.add(0, 1, 1, "菜单2").setIcon(R.drawable.icon02);

menu.add(0, 2, 2, "菜单3").setIcon(R.drawable.icon03);

menu.add(0, 3, 3, "菜单4");

menu.add(0, 4, 4, "菜单5");

menu.add(0, 5, 5, "菜单6");

menu.add(0, 6, 6, "菜单7").setIcon(R.drawable.icon04);

menu.add(0, 7, 7, "菜单8").setIcon(R.drawable.icon05);

return true;

}

// 重写 onOptionsItemSelected 用以响应选项菜单

@Override

public boolean onOptionsItemSelected(MenuItem item) {

super.onOptionsItemSelected(item);

Toast.makeText(Main.this, "被单击的菜单项为:" + String.valueOf(item.getItemId()), Toast.LENGTH_SHORT).show();

return false;

}

}

Android(3) - 对话框(Dialog)和通知(Notification)

介绍

在 Android 中种对话框及各种通知效果的应用

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常用对话框的使用,弹出式对话框、日期选择对话框、时间选择对话框、进度条对话框 通知(出现在通知列表)和提示性通知(Toast)的演示

1、常用对话框的演示

res/layout/main.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

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android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<TextView android:id="@+id/txtMsg" android:layout_width="wrap_content" android:layout_height="wrap_content"></TextView>

<Button android:id="@+id/btn1" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button>

<Button android:id="@+id/btn2" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button>

<Button android:id="@+id/btn3" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button>

<Button android:id="@+id/btn4" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button>

<Button android:id="@+id/btn5" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button>

<Button android:id="@+id/btn6" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button>

</LinearLayout>

res/layout/view.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<TextView android:text="我是一个 View"

android:layout_width="wrap_content" android:layout_height="wrap_content">

</TextView>

</LinearLayout>

res/values/array.xml

<?xml version="1.0" encoding="utf-8"?>

<resources>

<!--

定义一个名为 ary 的 string 类型的数组

-->

<string-array name="ary">

<item>项目 1</item>

<item>项目 2</item>

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</string-array>

</resources> Main.java 代码

package com.webabcd.dialog;

import java.util.Calendar;

import android.app.Activity;

import android.app.AlertDialog;

import android.app.DatePickerDialog;

import android.app.Dialog;

import android.app.ProgressDialog;

import android.app.TimePickerDialog;

import android.app.DatePickerDialog.OnDateSetListener;

import android.app.TimePickerDialog.OnTimeSetListener;

import android.content.DialogInterface;

import android.content.DialogInterface.OnClickListener;

import android.os.Bundle;

import android.view.View;

import android.widget.DatePicker;

import android.widget.TextView;

import android.widget.TimePicker;

import android.widget.Button;

public class Main extends Activity {

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

// 弹出式对话框的 Demo。先调用 Builder(),在 Create(), 需要显示对话框的是后再调用 show()

AlertDialog dialog = new AlertDialog.Builder(this).setTitle("弹出对话框").create();

dialog.show();

// 以下是各种对话框的 Demo

MyButtonClickListener listener = new MyButtonClickListener(); Button btn1 = (Button) this.findViewById(R.id.btn1);

btn1.setText("简单的对话框的 Demo");

btn1.setOnClickListener(listener);

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Button btn2 = (Button) this.findViewById(R.id.btn2); btn2.setText("包括常用设置的对话框(数据来自 xml)");

btn2.setOnClickListener(listener);

Button btn3 = (Button) this.findViewById(R.id.btn3); btn3.setText("弹出的对话框的内容是一个 View");

btn3.setOnClickListener(listener);

Button btn4 = (Button) this.findViewById(R.id.btn4); btn4.setText("日期选择对话框");

btn4.setOnClickListener(listener);

Button btn5 = (Button) this.findViewById(R.id.btn5); btn5.setText("时间选择对话框");

btn5.setOnClickListener(listener);

Button btn6 = (Button) this.findViewById(R.id.btn6); btn6.setText("进度条对话框");

btn6.setOnClickListener(listener);

}

class MyButtonClickListener implements View.OnClickListener { @Override

public void onClick(View v) {

// 具体的对话框的实现可以通过重写 onCreateDialog 完成

switch (v.getId()) {

case R.id.btn1:

Main.this.showDialog(0);

break;

case R.id.btn2:

Main.this.showDialog(1);

break;

case R.id.btn3:

Main.this.showDialog(2);

break;

case R.id.btn4:

Main.this.showDialog(3);

break;

case R.id.btn5:

Main.this.showDialog(4);

break;

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case R.id.btn6:

Main.this.showDialog(5);

break;

}

}

}

@Override

public Dialog onCreateDialog(int id) {

switch (id) {

case 0:

// 一个简单的弹出对话框

return new AlertDialog.Builder(this).setTitle("这是一个简单的弹出对话框的 Demo")

.create();

case 1:

// 一个相对复杂的弹出对话框

return new AlertDialog.Builder(this)

.setTitle("标题") // 设置标题

// .setCustomTitle(View) // 以一个 View 作为标题

.setIcon(R.drawable.icon01) // 设置标题图片

// .setMessage("信息") // 需要显示的弹出内容

.setPositiveButton("确定", new OnClickListener() { // 设置弹框的确认按钮所显示的文本,以及单击按钮后的响应行为

@Override

public void onClick(DialogInterface a0, int a1) { TextView txtMsg = (TextView) Main.this.findViewById(R.id.txtMsg);

txtMsg.append("单击了对话框上的“确认”按钮\n"); }

})

.setItems(R.array.ary, new DialogInterface.OnClickListener() { // 弹框所显示的内容来自一个数组。数组中的数据会一行一行地依次排列

public void onClick(DialogInterface dialog, int which) {

}

})

// 其他常用方法如下

// .setMultiChoiceItems(arg0, arg1, arg2)

// .setSingleChoiceItems(arg0, arg1, arg2)

// .setNeutralButton(arg0, arg1)

// .setNegativeButton(arg0, arg1)

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.create();

case 2:

// 弹出对话框为指定的 View 的 Demo

return new AlertDialog.Builder(this).setTitle("此对话框的内容是一个 View")

.setView(this.findViewById(R.layout.view)).create();

case 3:

// 弹出日期选择对话框

Calendar c = Calendar.getInstance();

return new DatePickerDialog(this, new OnDateSetListener() { @Override

public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {

TextView txtMsg = (TextView) Main.this.findViewById(R.id.txtMsg);

txtMsg.append("新设置的日期为:" + String.valueOf(year) + "-"

+ String.valueOf(monthOfYear) + "-"

+ String.valueOf(dayOfMonth) + "\n");

}

}, c.get(Calendar.YEAR), c.get(Calendar.MONTH), c.get(Calendar.DATE));

case 4:

// 弹出时间选择对话框

Calendar c2 = Calendar.getInstance();

return new TimePickerDialog(this, new OnTimeSetListener() { @Override

public void onTimeSet(TimePicker view, int hourOfDay, int minute) {

TextView txtMsg = (TextView) Main.this.findViewById(R.id.txtMsg);

txtMsg.append("新设置的时间为:"

+ String.valueOf(hourOfDay) + ":"

+ String.valueOf(minute) + "\n");

}

}, c2.get(Calendar.HOUR), c2.get(Calendar.MINUTE), true);

case 5:

// 弹出进度条对话框

ProgressDialog progress = new ProgressDialog(this);

16

progress.setMessage("loading...");

return progress;

default: return null;

}

}

}

2、各种提示效果的演示

res/layout/main.xml 代码

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<Button android:id="@+id/btn1" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button>

<Button android:id="@+id/btn2" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button>

<Button android:id="@+id/btn3" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button>

<Button android:id="@+id/btn4" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button>

</LinearLayout>

res/layout/view.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<TextView android:id="@+id/txtMsg" android:layout_width="wrap_content" android:layout_height="wrap_content">

</TextView>

</LinearLayout>

Main.java

代码

17

package com.webabcd.notification;

import android.app.Activity;

import android.app.Notification;

import android.app.NotificationManager;

import android.app.PendingIntent;

import android.content.Context;

import android.content.Intent;

import android.os.Bundle;

import android.util.Log;

import android.view.LayoutInflater;

import android.view.View;

import android.widget.Button;

import android.widget.TextView;

import android.widget.Toast;

public class Main extends Activity {

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

// 通过 Tost.makeText().show() 来实现提示性的通知效果

// 短时间的提示性通知的 Demo

Button btn1 = (Button) this.findViewById(R.id.btn1);

btn1.setText("短时间提示");

btn1.setOnClickListener(new Button.OnClickListener() {

public void onClick(View v) {

Toast.makeText(Main.this, "我是短时间提示", Toast.LENGTH_SHORT).show();

}

});

// 长时间的提示性通知的 Demo

Button btn2 = (Button) this.findViewById(R.id.btn2);

btn2.setText("长时间提示");

btn2.setOnClickListener(new Button.OnClickListener() {

public void onClick(View v) {

Toast.makeText(Main.this, "我是长时间提示", Toast.LENGTH_LONG).show();

}

});

18

// 以一个 View 作为提示性通知的 Demo

Button btn3 = (Button) this.findViewById(R.id.btn3);

btn3.setText("以一个 View 做提示");

btn3.setOnClickListener(new Button.OnClickListener() {

public void onClick(View v) {

View view = inflateView(R.layout.view);

TextView txtMsg = (TextView) view.findViewById(R.id.txtMsg); txtMsg.setText("提示内容");

Toast toast = new Toast(Main.this);

toast.setView(view);

toast.setDuration(Toast.LENGTH_LONG);

toast.show();

}

});

Button btn4 = (Button) this.findViewById(R.id.btn4);

btn4.setText("发出一个通知(Notification)");

btn4.setOnClickListener(new Button.OnClickListener() {

public void onClick(View v) {

// 实例化通知管理器

NotificationManager nm = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);

// 指定单击通知后所打开的详细的通知页面(单击通知后打开 NotificationView)

PendingIntent contentIntent = PendingIntent.getActivity( Main.this, 0, new Intent(Main.this, NotificationView.class), 0);

// 实例化一个通知,并指定其图标和标题(在提示栏上显示)

Notification n = new Notification(R.drawable.icon01, "我是滚动的通知信息我是滚动的通知信息我是滚动的通知信息", System.currentTimeMillis());

// 设置通知的发送人和通知的详细内容(打开提示栏后在通知列表中显示) n.setLatestEventInfo(Main.this, "通知发送人", "我是详细的通知信息我是详细的通知信息我是详细的通知信息", contentIntent);

// 100 毫秒延迟后,震动 250 毫秒,暂停 100 毫秒后,再震动 500 毫秒 n.vibrate = new long[] { 100, 250, 100, 500 };

// 发出通知(其中第一个参数为通知标识符)

19

nm.notify(0, n);

}

}); }

// 将指定的 xml 资源转换为一个 View

private View inflateView(int resource) {

LayoutInflater vi = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);

return vi.inflate(resource, null);

}

// 打开详细通知页后此 Activity 会被 Pause,从详细通知页返回后此 Activity 会被 Resume

@Override

protected void onPause() {

// TODO Auto-generated method stub

super.onPause();

Log.d("MyDebug", "onPause");

}

@Override

protected void onResume() {

// TODO Auto-generated method stub

super.onResume();

Log.d("MyDebug", "onResume");

}

}

NotificationView.java

代码

package com.webabcd.notification;

import android.app.Activity;

import android.app.NotificationManager;

import android.os.Bundle;

import android.widget.TextView;

// 单击通知列表的某个通知后,所打开的详细的通知页

public class NotificationView extends Activity {

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

20

setContentView(R.layout.view);

TextView txtMsg = (TextView)this.findViewById(R.id.txtMsg);

txtMsg.setText("点通知之后所链接到的 Activity");

NotificationManager nm = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);

// 取消显示在通知列表中的指定通知(参数为通知标识符)

nm.cancel(0);

// 需要关闭此 Activity 的话就 finish 它既可

// this.finish();

}

}

Android(4) - 活动(Activity), 服务(Service), 广播(Broadcast), 广播接收器(BroadcastReceiver)

介绍

在 Android 中使用 Activity, Service, Broadcast, BroadcastReceiver 活动(Activity) - 用于表现功能

服务(Service) - 相当于后台运行的 Activity

广播(Broadcast) - 用于发送广播

广播接收器(BroadcastReceiver) - 用于接收广播

Intent - 用于连接以上各个组件,并在其间传递消息

1、演示 Activity 的基本用法,一个 Activity 启动另一个 Activity,启动另一个 Activity 时为其传递参数,被启动的 Activity 返回参数给启动者的 Activity

Main.java

代码

package com.webabcd.activity;

import android.app.Activity;

import android.content.Intent;

import android.os.Bundle;

import android.util.Log;

import android.view.View;

import android.widget.Button;

21

import android.widget.TextView;

public class Main extends Activity {

TextView txt;

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

this.setContentView(R.layout.main);

txt = (TextView) this.findViewById(R.id.txt);

txt.setText("Activity 1");

Button btn = (Button) this.findViewById(R.id.btn);

btn.setText("启动另一个Activity");

btn.setOnClickListener(new Button.OnClickListener() { @Override

public void onClick(View v) {

// 实例化 Intent,指定需要启动的 Activity

Intent intent = new Intent();

intent.setClass(Main.this, MyActivity.class);

// 实例化 Bundle,设置需要传递的参数

Bundle bundle = new Bundle();

bundle.putString("name", "webabcd");

bundle.putDouble("salary", 100.13);

// 将需要传递的参数赋值给 Intent 对象

intent.putExtras(bundle);

// startActivity(intent); // 启动指定的 Intent(不等待返回结果)

// Main.this.finish();

// 启动指定的 Intent,并等待返回结果

// 其中第二个参数如果大于等于零,则返回结果时会回调 onActivityResult() 方法

startActivityForResult(intent, 0);

}

});

22

Log.d("MyDebug", "onCreate");

}

// 被启动的 Activity 返回结果时的回调函数

@Override

protected void onActivityResult(int requestCode, int resultCode, Intent data) {

if (resultCode == Activity.RESULT_OK){

Bundle bundle = data.getExtras();

String name = bundle.getString("name");

double salary = bundle.getDouble("salary");

txt.setText("Activity 1" + "\n名字:" + name + "\n薪水:" + String.valueOf(salary));

}

}

@Override

protected void onStart() {

// TODO Auto-generated method stub

super.onStart();

Log.d("MyDebug", "onStart");

}

@Override

protected void onStop() {

// TODO Auto-generated method stub

super.onStop();

Log.d("MyDebug", "onStop");

}

@Override

protected void onRestart() {

// TODO Auto-generated method stub

super.onRestart();

Log.d("MyDebug", "onRestart");

}

@Override

protected void onPause() {

23

// TODO Auto-generated method stub

super.onPause();

Log.d("MyDebug", "onPause");

}

@Override

protected void onResume() {

// TODO Auto-generated method stub

super.onResume();

Log.d("MyDebug", "onResume");

}

@Override

protected void onDestroy() {

// TODO Auto-generated method stub

super.onDestroy();

Log.d("MyDebug", "onDestroy");

}

}

MyActivity.java

代码

package com.webabcd.activity;

import android.app.Activity;

import android.content.Intent;

import android.os.Bundle;

import android.view.View;

import android.widget.Button;

import android.widget.TextView;

// 被另一个 Activity 所启动的 Activity

public class MyActivity extends Activity {

Intent intent;

/** Called when the activity is first created. */ @Override

public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState);

24

this.setContentView(R.layout.main2);

// 获取启动者传递过来的参数

intent = this.getIntent();

Bundle bundle = intent.getExtras();

String name = bundle.getString("name");

double salary = bundle.getDouble("salary");

TextView txt = (TextView) this.findViewById(R.id.txt);

txt.setText("Activity 2" + "\n名字:" + name + "\n薪水:" + String.valueOf(salary));

Button btn = (Button) this.findViewById(R.id.btn);

btn.setText("返回前一个Activity");

btn.setOnClickListener(new Button.OnClickListener() { public void onClick(View v) {

// 返回参数给启动者

MyActivity.this.setResult(Activity.RESULT_OK, intent);

MyActivity.this.finish();

}

});

}

}

AndroidManifest.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<manifest

xmlns:android="/apk/res/android" package="com.webabcd.activity" android:versionCode="1" android:versionName="1.0">

<application android:icon="@drawable/icon" android:label="@string/app_name">

<activity android:name=".Main" android:label="@string/app_name">

<intent-filter>

<action android:name="android.intent.action.MAIN" />

<category

android:name="android.intent.category.LAUNCHER" />

</intent-filter>

25

</activity>

<!--

如果有需要用到的 Activity ,则都要在这里做相应的配置 -->

<activity android:name=".MyActivity" android:label="Activity 2" />

</application>

<uses-sdk android:minSdkVersion="3" />

</manifest>

2、Service, Broadcast, BroadcastReceiver 的演示

Main.java

代码

package com.webabcd.service;

import android.app.Activity;

import android.content.BroadcastReceiver;

import android.content.ComponentName;

import android.content.Context;

import android.content.Intent;

import android.content.IntentFilter;

import android.content.ServiceConnection;

import android.os.Bundle;

import android.os.IBinder;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.TextView;

/*

* startService() 和 bindService() 的区别

* startService() - 正常理解就好

* bindService() - 使当前上下文对象(本例中就是 Activity)通过一个 ServiceConnection 对象邦定到指定的 Service 。这样,如果上下文对象销毁了的话,那么其对应的 Service 也会被销毁

*/

public class Main extends Activity implements OnClickListener {

private TextView txtMsg;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

26

setContentView(R.layout.main);

setTitle("android 之 service");

this.findViewById(R.id.btnStart).setOnClickListener(this); this.findViewById(R.id.btnStop).setOnClickListener(this); this.findViewById(R.id.btnBind).setOnClickListener(this); this.findViewById(R.id.btnUnbind).setOnClickListener(this);

txtMsg = (TextView)this.findViewById(R.id.txtMsg);

// 实例化自定义的 BroadcastReceiver

receiver = new UpdateReceiver();

IntentFilter filter = new IntentFilter();

// 为 BroadcastReceiver 指定 action ,使之用于接收同 action 的广播

filter.addAction("com.webabcd.service.msg");

// 以编程方式注册 BroadcastReceiver 。配置方式注册 BroadcastReceiver 的例子见 AndroidManifest.xml 文件

// 一般在 OnStart 时注册,在 OnStop 时取消注册

this.registerReceiver(receiver, filter);

// this.unregisterReceiver(receiver);

}

@Override

public void onClick(View v) {

Intent intent = new Intent(Main.this, MyService.class); switch (v.getId()) {

case R.id.btnStart:

this.startService(intent);

break;

case R.id.btnStop:

this.stopService(intent);

break;

case R.id.btnBind:

this.bindService(intent, conn, Context.BIND_AUTO_CREATE);

break;

case R.id.btnUnbind:

this.unbindService(conn);

break;

}

27

}

// bindService() 所需的 ServiceConnection 对象

private ServiceConnection conn = new ServiceConnection() { @Override

public void onServiceConnected(ComponentName className, IBinder service) {

}

@Override

public void onServiceDisconnected(ComponentName className) {

}

};

private String msg="";

private UpdateReceiver receiver;

// 实现一个 BroadcastReceiver,用于接收指定的 Broadcast

public class UpdateReceiver extends BroadcastReceiver{

@Override

public void onReceive(Context context, Intent intent) { msg = intent.getStringExtra("msg");

txtMsg.append(msg + "\n");

}

}

}

MyService.java

代码

package com.webabcd.service;

import android.app.Service;

import android.content.Intent;

import android.os.IBinder;

import android.util.Log;

// 演示 Service 的生命周期。具体信息运行程序后在 LogCat 中查看 public class MyService extends Service {

28

@Override

public IBinder onBind(Intent intent) {

Log.d("MyDebug", "onBind");

sendMsg("onBind");

// TODO Auto-generated method stub return null;

}

@Override

public void onCreate() {

// TODO Auto-generated method stub super.onCreate();

Log.d("MyDebug", "onCreate");

sendMsg("onCreate");

}

@Override

public void onDestroy() {

// TODO Auto-generated method stub super.onDestroy();

Log.d("MyDebug", "onDestroy");

sendMsg("onDestroy");

}

@Override

public void onRebind(Intent intent) {

// TODO Auto-generated method stub super.onRebind(intent);

Log.d("MyDebug", "onRebind");

sendMsg("onRebind");

}

@Override

public void onStart(Intent intent, int startId) { super.onStart(intent, startId);

Log.d("MyDebug", "onStart");

sendMsg("onStart");

}

29

@Override

public boolean onUnbind(Intent intent) {

Log.d("MyDebug", "onUnbind");

sendMsg("onUnbind");

// TODO Auto-generated method stub

return super.onUnbind(intent);

}

// 发送广播信息

private void sendMsg(String msg){

// 指定广播目标的 action (注:指定了此 action 的 receiver 会接收此广播)

Intent intent = new Intent("com.webabcd.service.msg"); // 需要传递的参数

intent.putExtra("msg", msg);

// 发送广播

this.sendBroadcast(intent);

}

}

MyBootReceiver.java

代码

package com.webabcd.service;

import android.content.BroadcastReceiver;

import android.content.Context;

import android.content.Intent;

import android.util.Log;

public class MyBootReceiver extends BroadcastReceiver {

// 用于接收满足条件的 Broadcast(相应的 Broadcast 的注册信息详见 AndroidManifest.xml ,当系统启动完毕后会调用这个广播接收器)

@Override

public void onReceive(Context arg0, Intent arg1) {

Log.d("MyDebug", "onReceive");

// 启动服务

Intent service = new Intent(arg0, MyService.class);

30

arg0.startService(service);

}

}

AndroidManifest.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<manifest

xmlns:android="/apk/res/android" package="com.webabcd.service" android:versionCode="1" android:versionName="1.0">

<application android:icon="@drawable/icon" android:label="@string/app_name">

<activity android:name=".Main" android:label="@string/app_name">

<intent-filter>

<action android:name="android.intent.action.MAIN" />

<category

android:name="android.intent.category.LAUNCHER" />

</intent-filter>

</activity>

<!--

如果有需要用到的 service ,则都要在这里做相应的配置 -->

<service android:name=".MyService"></service>

<!--

注册一个 BroadcastReceiver

其 intent-filter 为 android.intent.action.BOOT_COMPLETED(用于接收系统启动完毕的 Broadcast)

-->

<receiver android:name=".MyBootReceiver">

<intent-filter>

<action

android:name="android.intent.action.BOOT_COMPLETED" /> </intent-filter>

</receiver>

</application>

31

<!--

接受系统启动完毕的 Broadcast 的权限

-->

<uses-permission

android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

<uses-sdk android:minSdkVersion="3" />

</manifest>

Android(5) - 控件(View)之TextView, Button, ImageButton, ImageView, CheckBox, RadioButton, AnalogClock, DigitalClock

介绍

在 Android 中使用各种控件(View)

?

?

?

?

?

?

?

? TextView - 文本显示控件 Button - 按钮控件 ImageButton - 图片按钮控件 ImageView - 图片显示控件 CheckBox - 复选框控件 RadioButton - 单选框控件 AnalogClock - 钟表(带表盘的那种)控件 DigitalClock - 电子表控件

1、TextView 的 Demo

textview.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<!--

TextView - 文本显示控件

-->

<TextView android:layout_width="fill_parent"

android:layout_height="wrap_content" android:id="@+id/textVie

32

w" />

</LinearLayout>

_TextView.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.os.Bundle;

import android.widget.TextView;

public class _TextView extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.textview);

// 设置 Activity 的标题

setTitle("TextView");

TextView txt = (TextView) this.findViewById(R.id.textView); // 设置文本显示控件的文本内容,需要换行的话就用“\n”

txt.setText("我是 TextView\n显示文字用的");

}

}

2、Button 的 Demo

button.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<TextView android:layout_width="fill_parent"

android:layout_height="wrap_content" android:id="@+id/textView" />

<!--

33

Button - 按钮控件

-->

<Button android:id="@+id/button"

android:layout_width="wrap_content" android:layout_height="wrap_content">

</Button>

</LinearLayout>

_Button.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.widget.Button;

import android.widget.TextView;

public class _Button extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.button);

setTitle("Button");

Button btn = (Button) this.findViewById(R.id.button); btn.setText("click me");

// setOnClickListener() - 响应按钮的鼠标单击事件

btn.setOnClickListener(new Button.OnClickListener(){

@Override

public void onClick(View v) {

TextView txt = (TextView) _Button.this.findViewById(R.id.textView);

txt.setText("按钮被单击了");

}

});

}

}

34

3、ImageButton 的 Demo

imagebutton.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<TextView android:layout_width="fill_parent"

android:layout_height="wrap_content" android:id="@+id/textView" />

<!--

ImageButton - 图片按钮控件

-->

<ImageButton android:id="@+id/imageButton"

android:layout_width="wrap_content" android:layout_height="wrap_content">

</ImageButton>

</LinearLayout>

_ImageButton.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.widget.Button;

import android.widget.ImageButton;

import android.widget.TextView;

public class _ImageButton extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.imagebutton);

35

setTitle("ImageButton");

ImageButton imgButton = (ImageButton) this.findViewById(R.id.imageButton);

// 设置图片按钮的背景

imgButton.setBackgroundResource(R.drawable.icon01);

// setOnClickListener() - 响应图片按钮的鼠标单击事件

imgButton.setOnClickListener(new Button.OnClickListener(){ @Override

public void onClick(View v) {

TextView txt = (TextView) _ImageButton.this.findViewById(R.id.textView);

txt.setText("图片按钮被单击了");

}

});

}

}

4、ImageView 的 Demo

imageview.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<!--

ImageView - 图片显示控件

-->

<ImageView android:id="@+id/imageView" android:layout_width="wrap_content"

android:layout_height="wrap_content"></ImageView>

</LinearLayout>

_ImageView.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.os.Bundle;

36

import android.widget.ImageView;

public class _ImageView extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.imageview);

setTitle("ImageView");

ImageView imgView = (ImageView) this.findViewById(R.id.imageView);

// 指定需要显示的图片

imgView.setBackgroundResource(R.drawable.icon01);

}

}

5、CheckBox 的 Demo

checkbox.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<TextView android:layout_width="fill_parent"

android:layout_height="wrap_content" android:id="@+id/textView" />

<!--

CheckBox - 复选框控件

-->

<CheckBox android:text="CheckBox01" android:id="@+id/chk1"

android:layout_width="wrap_content" android:layout_height="wrap_content"></CheckBox>

<CheckBox android:text="CheckBox02" android:id="@+id/chk2"

android:layout_width="wrap_content" android:layout_height="wrap_content"></CheckBox>

<CheckBox android:text="CheckBox03" android:id="@+id/chk3"

android:layout_width="wrap_content" android:layout_height="wr

37

ap_content"></CheckBox>

</LinearLayout>

_CheckBox.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.os.Bundle;

import android.widget.CheckBox;

import android.widget.CompoundButton;

import android.widget.TextView;

public class _CheckBox extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.checkbox);

setTitle("CheckBox");

CheckBox chk = (CheckBox) this.findViewById(R.id.chk1);

// setOnCheckedChangeListener() - 响应复选框的选中状态改变事件

chk.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {

@Override

public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

TextView txt = (TextView) _CheckBox.this.findViewById(R.id.textView);

txt.setText("CheckBox01 的选中状态:

" + String.valueOf(isChecked));

}

});

}

}

6、RadioButton 的 Demo

radiobutton.xml

38

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<TextView android:layout_width="fill_parent"

android:layout_height="wrap_content" android:id="@+id/textView" />

<!--

RadioButton - 单选框控件

RadioGroup - 对其内的单选框控件做分组

checkedButton - 指定组内被选中的单选框的 ID

-->

<RadioGroup android:id="@+id/radioGroup"

android:layout_width="fill_parent" android:layout_height="fill_parent"

android:checkedButton="@+id/rad3" android:orientation="horizontal"

android:gravity="center_vertical|center_horizontal">

<RadioButton android:text="rad1" android:id="@+id/rad1"

android:layout_width="wrap_content" android:layout_height="wrap_content"></RadioButton>

<RadioButton android:text="rad2" android:id="@+id/rad2"

android:layout_width="wrap_content" android:layout_height="wrap_content"></RadioButton>

<RadioButton android:text="rad3" android:id="@+id/rad3"

android:layout_width="wrap_content" android:layout_height="wrap_content"></RadioButton>

</RadioGroup>

</LinearLayout>

_RadioButton.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.os.Bundle;

import android.widget.RadioButton;

import android.widget.RadioGroup;

import android.widget.TextView;

39

public class _RadioButton extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.radiobutton);

setTitle("RadioButton");

RadioGroup group = (RadioGroup) this.findViewById(R.id.radioGroup);

// setOnCheckedChangeListener() - 响应单选框组内的选中项发生变化时的事件

group.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {

@Override

public void onCheckedChanged(RadioGroup group, int checkedId) {

TextView txt = (TextView) _RadioButton.this.findViewById(R.id.textView);

txt.setText(((RadioButton)findViewById(checkedId)).getText() + " 被选中");

}

});

}

}

7、AnalogClock 的 Demo

analogclock.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<!--

AnalogClock - 钟表(带表盘的那种)控件

-->

<AnalogClock android:id="@+id/analogClock"

android:layout_width="wrap_content" android:layout_height="wr

40

ap_content">

</AnalogClock>

</LinearLayout>

_AnalogClock.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.os.Bundle;

public class _AnalogClock extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.analogclcok);

setTitle("AnalogClock");

}

}

8、DigitalClock 的 Demo

digitalclock.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<!--

DigitalClock - 电子表控件

-->

<DigitalClock android:id="@+id/digitalClock"

android:layout_width="wrap_content" android:layout_height="wrap_content">

</DigitalClock>

</LinearLayout>

41

_DigitalClock.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.os.Bundle;

public class _DigitalClock extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.digitalclcok);

setTitle("DigitalClcok");

}

}

Android(6) - 控件(View)之DatePicker, TimePicker, ToggleButton, EditText, ProgressBar, SeekBar, AutoCompleteTextView, MultiAutoCompleteTextView

介绍

在 Android 中使用各种控件(View)

?

?

?

?

?

?

?

? DatePicker - 日期选择控件 TimePicker - 时间选择控件 ToggleButton - 双状态按钮控件 EditText - 可编辑文本控件 ProgressBar - 进度条控件 SeekBar - 可拖动的进度条控件 AutoCompleteTextView - 支持自动完成功能的可编辑文本控件 MultiAutoCompleteTextView - 支持自动完成功能的可编辑文本控件,允

许输入多值(多值之间会自动地用指定的分隔符分开)

42

1、DatePicker 的 Demo

datepicker.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<!--

DatePicker - 日期选择控件

-->

<DatePicker android:id="@+id/datePicker"

android:layout_width="wrap_content" android:layout_height="wrap_content">

</DatePicker>

</LinearLayout>

_DatePicker.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.os.Bundle;

public class _DatePicker extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.datepicker);

// 具体的应用可参见对话框中的示例

setTitle("DatePicker");

}

}

2、TimePicker 的 Demo

timepicker.xml

43

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<!--

TimePicker - 时间选择控件

-->

<TimePicker android:id="@+id/timePicker"

android:layout_width="wrap_content" android:layout_height="wrap_content">

</TimePicker>

</LinearLayout>

_TimePicker.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.os.Bundle;

public class _TimePicker extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.timepicker);

// 具体的应用可参见对话框中的示例

setTitle("TimePicker");

}

}

3、ToggleButton 的 Demo

togglebutton.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

44

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<TextView android:layout_width="fill_parent"

android:layout_height="wrap_content" android:id="@+id/textView" />

<!--

ToggleButton - 双状态按钮控件

textOn - 当按钮状态为 true 时所显示的文本

textOff - 当按钮状态为 false 时所显示的文本

-->

<ToggleButton android:id="@+id/toggleButton"

android:layout_width="wrap_content" android:layout_height="wrap_content"

android:textOn="关闭" android:textOff="打开" />

</LinearLayout>

_ToggleButton.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.widget.Button;

import android.widget.TextView;

import android.widget.ToggleButton;

public class _ToggleButton extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.togglebutton);

setTitle("ToggleButton");

final ToggleButton btn = (ToggleButton) this.findViewById(R.id.toggleButton);

// setOnClickListener() - 响应按钮的鼠标单击事件

btn.setOnClickListener(new Button.OnClickListener(){

45

@Override

public void onClick(View v) {

TextView txt = (TextView) _ToggleButton.this.findViewById(R.id.textView);

// ToggleButton.isChecked() - 双状态按钮的按钮状态 txt.setText("按钮状态:

" + String.valueOf(btn.isChecked()));

}

});

}

}

4、EditText 的 Demo

edittext.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<!--

EditText - 可编辑文本控件

-->

<EditText android:id="@+id/editText" android:layout_width="fill_parent"

android:layout_height="wrap_content">

</EditText>

</LinearLayout>

_EditText.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.os.Bundle;

import android.widget.EditText;

public class _EditText extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

46

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.edittext);

setTitle("EditText");

EditText txt = (EditText) this.findViewById(R.id.editText); txt.setText("我可编辑");

}

}

5、ProgressBar 的 Demo

progressbar.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<!--

ProgressBar - 进度条控件

-->

<!--以下分别为大、中、小的进度条控件(圆圈状)-->

<ProgressBar android:id="@+android:id/progress_large"

style="?android:attr/progressBarStyleLarge" android:layout_width="wrap_content"

android:layout_height="wrap_content" />

<ProgressBar android:id="@+android:id/progress"

android:layout_width="wrap_content" android:layout_height="wrap_content" />

<ProgressBar android:id="@+android:id/progress_small"

style="?android:attr/progressBarStyleSmall" android:layout_width="wrap_content"

android:layout_height="wrap_content" />

<!--

进度条控件(条状)的演示

style - 进度条的样式,本例使用内置样式

max - 进度的最大值

progress - 第一进度位置

secondaryProgress - 第二进度位置

47

-->

<ProgressBar android:id="@+id/progress_horizontal"

style="?android:attr/progressBarStyleHorizontal" android:layout_width="200px"

android:layout_height="wrap_content" android:max="100" android:progress="50" android:secondaryProgress="75" />

</LinearLayout>

_ProgressBar.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.os.Bundle;

import android.view.Window;

// 另见对话框中的进度条

public class _ProgressBar extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

// 设置特性以允许在应用程序的标题栏上显示进度条(条状) requestWindowFeature(Window.FEATURE_PROGRESS);

// 设置特性以允许在应用程序的标题栏上显示进度条(圆圈状)

requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);

this.setContentView(R.layout.progressbar);

setTitle("ProgressBar");

// 在标题栏上显示进度条(条状)

setProgressBarVisibility(true);

// 在标题栏上显示进度条(圆圈状)

setProgressBarIndeterminateVisibility(true);

// 指定进度条的进度

setProgress(50 * 100);

setSecondaryProgress(75 * 100);

48

}

}

6、SeekBar 的 Demo

seekbar.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<!--

SeekBar - 可拖动的进度条控件

max - 进度的最大值

progress - 第一进度位置

secondaryProgress - 第二进度位置

-->

<SeekBar android:id="@+id/seekBar" android:layout_width="fill_parent"

android:layout_height="wrap_content" android:max="100" android:progress="50" android:secondaryProgress="75" />

<TextView android:id="@+id/progress" android:layout_width="fill_parent"

android:layout_height="wrap_content" />

<TextView android:id="@+id/tracking" android:layout_width="fill_parent"

android:layout_height="wrap_content" />

</LinearLayout>

_SeekBar.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.os.Bundle;

import android.widget.SeekBar;

import android.widget.TextView;

public class _SeekBar extends Activity implements

49

SeekBar.OnSeekBarChangeListener {

SeekBar mSeekBar;

TextView mProgressText;

TextView mTrackingText;

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.seekbar);

setTitle("SeekBar");

mSeekBar = (SeekBar) findViewById(R.id.seekBar);

// setOnSeekBarChangeListener() - 响应拖动进度条事件 mSeekBar.setOnSeekBarChangeListener(this);

mProgressText = (TextView) findViewById(R.id.progress); mTrackingText = (TextView) findViewById(R.id.tracking); }

// 拖动进度条后,进度发生改变时的回调事件

public void onProgressChanged(SeekBar seekBar, int progress, boolean fromTouch) {

mProgressText.setText(progress + "%");

}

// 拖动进度条前开始跟踪触摸

public void onStartTrackingTouch(SeekBar seekBar) {

mTrackingText.setText("开始跟踪触摸");

}

// 拖动进度条后停止跟踪触摸

public void onStopTrackingTouch(SeekBar seekBar) {

mTrackingText.setText("停止跟踪触摸");

}

}

7、AutoCompleteTextView 的 Demo

autocompletetextview.xml

代码

50

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<!--

AutoCompleteTextView - 支持自动完成功能的可编辑文本控件 -->

<AutoCompleteTextView android:id="@+id/editText"

android:layout_width="fill_parent" android:layout_height="wrap_content" />

</LinearLayout>

_AutoCompleteTextView.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.os.Bundle;

import android.widget.ArrayAdapter;

import android.widget.AutoCompleteTextView;

public class _AutoCompleteTextView extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.autocompletetextview);

setTitle("AutoCompleteTextView");

// 实例化适配器,指定显示格式及数据源

ArrayAdapter<String> adapter = new ArrayAdapter<String>( this,

android.R.layout.simple_dropdown_item_1line,

ary);

AutoCompleteTextView textView = (AutoCompleteTextView) findViewById(R.id.editText);

// 指定自动完成控件的适配器

textView.setAdapter(adapter);

}

51

// 自动完成控件的所需数据的数据源

private String[] ary = new String[] {

"abc",

"abcd",

"abcde",

"abcdef",

"abcdefg",

"hij",

"hijk",

"hijkl",

"hijklm",

"hijklmn",

};

}

8、MultiAutoCompleteTextView 的 Demo

multiautocompletetextview.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<!--

MultiAutoCompleteTextView - 支持自动完成功能的可编辑文本控件,允许输入多值(多值之间会自动地用指定的分隔符分开)

-->

<MultiAutoCompleteTextView android:id="@+id/editText"

android:layout_width="fill_parent" android:layout_height="wrap_content" />

</LinearLayout>

_MultiAutoCompleteTextView.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.os.Bundle;

import android.widget.ArrayAdapter;

import android.widget.MultiAutoCompleteTextView;

52

public class _MultiAutoCompleteTextView extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.multiautocompletetextview);

setTitle("MultiAutoCompleteTextView");

// 实例化适配器,指定显示格式及数据源

ArrayAdapter<String> adapter = new ArrayAdapter<String>( this,

android.R.layout.simple_dropdown_item_1line, ary);

MultiAutoCompleteTextView textView = (MultiAutoCompleteTextView) findViewById(R.id.editText);

textView.setAdapter(adapter);

// 设置多个值之间的分隔符,此处为逗号

textView.setTokenizer(new MultiAutoCompleteTextView.CommaTokenizer());

}

// 自动完成控件的所需数据的数据源

private String[] ary = new String[] {

"abc",

"abcd",

"abcde",

"abcdef",

"abcdefg",

"hij",

"hijk",

"hijkl",

"hijklm",

"hijklmn",

};

}

53

Android(7) - 控件(View)之ZoomControls, Include, VideoView, WebView, RatingBar, Tab, Spinner, Chronometer, ScrollView 介绍

在 Android 中使用各种控件(View)

?

?

?

?

?

?

?

?

? ZoomControls - 放大/缩小按钮控件 Include - 整合控件 VideoView - 视频播放控件 WebView - 浏览器控件 RatingBar - 评分控件 Tab - 选项卡控件 Spinner - 下拉框控件 Chronometer - 计时器控件 ScrollView - 滚动条控件

1、ZoomControls 的 Demo

zoomcontrols.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<!--

放大/缩小按钮控件

-->

<ZoomControls android:id="@+id/zoomControls"

android:layout_width="wrap_content" android:layout_height="wrap_content"></ZoomControls>

</LinearLayout>

_ZoomControls.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

54

import android.view.View.OnClickListener;

import android.widget.Toast;

import android.widget.ZoomControls;

public class _ZoomControls extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.zoomcontrols);

setTitle("ZoomControls");

ZoomControls zoomControls = (ZoomControls) this.findViewById(R.id.zoomControls);

// setOnZoomInClickListener() - 响应单击放大按钮的事件

zoomControls.setOnZoomInClickListener(new OnClickListener() { public void onClick(View v) {

Toast.makeText(_ZoomControls.this, "单击了放大按钮", Toast.LENGTH_SHORT).show();

}

});

// setOnZoomOutClickListener() - 响应单击缩小按钮的事件

zoomControls.setOnZoomOutClickListener(new OnClickListener() {

public void onClick(View v) {

Toast.makeText(_ZoomControls.this, "单击了缩小按钮", Toast.LENGTH_SHORT).show();

}

});

}

}

2、Include 的 Demo

include.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent"

55

android:layout_height="fill_parent">

<!--

include - 整合控件,将指定的 layout 整合进来

layout - 指定需要整合 layout

-->

<include android:id="@+id/cell1" layout="@layout/include_1" /> <include android:id="@+id/cell2" android:layout_width="fill_parent" layout="@layout/include_2" />

</LinearLayout>

include_1.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<TextView xmlns:android="/apk/res/android" android:text="TextView01" android:layout_width="wrap_content" android:layout_height="wrap_content">

</TextView>

include_2.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<TextView xmlns:android="/apk/res/android" android:text="TextView02" android:layout_width="wrap_content" android:layout_height="wrap_content">

</TextView>

_Include.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.os.Bundle;

public class _Include extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.include);

56

setTitle("Include");

}

}

3、VideoView 的 Demo

videoview.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<!--

VideoView - 视频播放控件

-->

<VideoView android:id="@+id/videoView" android:layout_width="wrap_content"

android:layout_height="wrap_content">

</VideoView>

</LinearLayout>

_VideoView.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.net.Uri;

import android.os.Bundle;

import android.widget.MediaController;

import android.widget.VideoView;

public class _VideoView extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.videoview);

setTitle("VideoView");

57

VideoView videoView = (VideoView) findViewById(R.id.videoView);

// 指定需要播放的视频的地址

videoView.setVideoURI(Uri.parse("android.resource://com.webabcd.view/" + R.raw.demo));

// videoView.setVideoPath();

// 设置播放器的控制条

videoView.setMediaController(new MediaController(this)); // 开始播放视频

videoView.start();

}

}

4、WebView 的 Demo

webview.xml 代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<!--

WebView - 浏览器控件(WebKit 内核)

-->

<WebView android:layout_width="fill_parent"

android:layout_height="wrap_content" android:id="@+id/webView" />

</LinearLayout>

_WebView.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.os.Bundle;

import android.webkit.WebSettings;

import android.webkit.WebView;

public class _WebView extends Activity {

58

@Override

protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.webview);

setTitle("WebView");

WebView webView = (WebView) findViewById(R.id.webView);

// 配置浏览器,使其可支持 JavaScript

WebSettings webSettings = webView.getSettings();

webSettings.setJavaScriptEnabled(true);

// 清除浏览器缓存

webView.clearCache(true);

// 指定浏览器需要解析的 url 地址

webView.loadUrl("/");

// 指定浏览器需要解析的 html 数据

// webView.loadData("<a href='/'>webabcd</a>", "text/html", "utf-8");

}

}

5、RatingBar 的 Demo

ratingbar.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<!--

RatingBar - 评分控件

numStars - 评分控件的星星的数量

rating - 当前评分的值

-->

<RatingBar android:id="@+id/ratingBar" android:numStars="5" android:rating="1.5" android:layout_width="wrap_content" android:layout_height="wrap_content">

</RatingBar>

59

<TextView android:id="@+id/textView" android:layout_width="wrap_content"

android:layout_height="wrap_content" />

</LinearLayout>

_RatingBar.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.os.Bundle;

import android.widget.RatingBar;

import android.widget.TextView;

public class _RatingBar extends Activity implements RatingBar.OnRatingBarChangeListener {

private RatingBar mRatingBar;

private TextView mTextView;

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.ratingbar);

setTitle("RatingBar");

mTextView = (TextView) findViewById(R.id.textView);

mRatingBar = (RatingBar) findViewById(R.id.ratingBar);

// setOnRatingBarChangeListener() - 响应评分值发生改变的事件 mRatingBar.setOnRatingBarChangeListener(this);

}

@Override

public void onRatingChanged(RatingBar ratingBar, float rating, boolean fromUser) {

mTextView.setText(String.valueOf(rating));

}

}

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6、Tab 的 Demo

tab.xml 代码

<?xml version="1.0" encoding="utf-8"?>

<FrameLayout xmlns:android="/apk/res/android"

android:layout_width="fill_parent" android:layout_height="fill_parent">

<!-- Tab 1 的内容 -->

<TextView android:id="@+id/view1" android:layout_width="fill_parent"

android:layout_height="fill_parent" android:text="tab1 content" />

<!-- Tab 2 的内容 -->

<TextView android:id="@+id/view2" android:layout_width="fill_parent"

android:layout_height="fill_parent" android:text="tab2 content" />

</FrameLayout>

_Tab.java 代码

package com.webabcd.view;

import android.app.TabActivity;

import android.content.Intent;

import android.os.Bundle;

import android.view.LayoutInflater;

import android.widget.TabHost;

// 实现 Tab 功能的话要继承 TabActivity

public class _Tab extends TabActivity {

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

TabHost tabHost = getTabHost();

61

LayoutInflater.from(this).inflate(R.layout.tab, tabHost.getTabContentView(), true);

// Tab 1 的内容

tabHost.addTab(tabHost.newTabSpec("tab1")

.setIndicator("tab1") .setContent(R.id.view1));

// Tab 2 的内容(设置了 Tab 图片)

tabHost.addTab(tabHost.newTabSpec("tab2")

.setIndicator("tab2", getResources().getDrawable(R.drawable.icon01))

.setContent(R.id.view2));

// Tab 3 的内容(设置 Tab 的内容为指定的 Activity)

tabHost.addTab(tabHost.newTabSpec("tab3") .setIndicator("tab3")

.setContent(new Intent(this, _TextView.class)));

}

}

7、Spinner 的 Demo

spinner.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<TextView android:layout_width="fill_parent"

android:layout_height="wrap_content" android:id="@+id/textView" />

<!--

Spinner - 下拉框控件

-->

<Spinner android:id="@+id/spinner" android:layout_width="fill_parent"

android:layout_height="wrap_content" />

</LinearLayout>

62

_Spinner.java 代码

package com.webabcd.view;

import android.app.Activity; import android.os.Bundle;

import android.view.View;

import android.widget.AdapterView;

import android.widget.ArrayAdapter;

import android.widget.Spinner;

import android.widget.TextView;

public class _Spinner extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.spinner);

setTitle("Spinner");

Spinner spinner = (Spinner) findViewById(R.id.spinner);

// 设置下拉框控件的标题文本

spinner.setPrompt("请选择");

// 实例化适配器,指定显示格式及数据源

ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(

this, R.array.colors, android.R.layout.simple_spinner_item); adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

spinner.setAdapter(adapter);

// setOnItemSelectedListener() - 响应下拉框的选中值发生变化的事件

spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {

@Override

public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) {

TextView textView = (TextView)_Spinner.this.findViewB

63

yId(R.id.textView);

textView.setText(((TextView)arg1).getText());

}

@Override

public void onNothingSelected(AdapterView<?> arg0) {

}

});

}

}

8、Chronometer 的 Demo

chronometer.xml 代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<!--

Chronometer - 计时器控件

-->

<Chronometer android:id="@+id/chronometer"

android:layout_width="wrap_content" android:layout_height="wrap_content" />

<Button android:id="@+id/btnStart" android:layout_width="wrap_content"

android:layout_height="wrap_content" android:text="开始计时"> <requestFocus /> </Button>

<Button android:id="@+id/btnStop" android:layout_width="wrap_content"

android:layout_height="wrap_content" android:text="停止计时"> </Button>

<Button android:id="@+id/btnReset" android:layout_width="wrap_content"

android:layout_height="wrap_content" android:text="计时器复位">

64

</Button>

</LinearLayout>

_Chronometer.java 代码

package com.webabcd.view;

import android.app.Activity; import android.os.Bundle;

import android.os.SystemClock;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.Chronometer;

public class _Chronometer extends Activity {

private Chronometer mChronometer;

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.chronometer);

setTitle("Chronometer");

Button button;

mChronometer = (Chronometer) findViewById(R.id.chronometer); // 设置计时器所显示的时间格式

mChronometer.setFormat("计时:(%s)");

button = (Button) findViewById(R.id.btnStart);

button.setOnClickListener(mStartListener);

button = (Button) findViewById(R.id.btnStop);

button.setOnClickListener(mStopListener);

button = (Button) findViewById(R.id.btnReset);

button.setOnClickListener(mResetListener);

}

65

View.OnClickListener mStartListener = new OnClickListener() { public void onClick(View v) {

// 启动计时器

mChronometer.start();

}

};

View.OnClickListener mStopListener = new OnClickListener() { public void onClick(View v) {

// 暂停计时器

mChronometer.stop();

}

};

View.OnClickListener mResetListener = new OnClickListener() { public void onClick(View v) {

// 复位计时器,即停止计时器

mChronometer.setBase(SystemClock.elapsedRealtime()); }

};

}

9、ScrollView 的 Demo

scrollview.xml 代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<!--

ScrollView - 滚动条控件

scrollbarStyle - 滚动条的样式

-->

<ScrollView android:id="@+id/scrollView"

android:layout_width="fill_parent" android:layout_height="200px"

android:scrollbarStyle="outsideOverlay" android:background="@android:drawable/edit_text">

<TextView android:layout_width="fill_parent"

android:layout_height="wrap_content" android:id="@+id/textView" />

66

</ScrollView>

</LinearLayout>

_ScrollView.java 代码

package com.webabcd.view;

import android.app.Activity; import android.os.Bundle;

import android.widget.TextView;

public class _ScrollView extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.scrollview);

setTitle("ScrollView");

TextView textView = (TextView)this.findViewById(R.id.textView);

textView.setText("a\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na");

}

}

Android(8) - 控件(View)之TextSwitcher, Gallery,

ImageSwitcher, GridView, ListView, ExpandableList

介绍

在 Android 中使用各种控件(View)

?

?

?

?

?

? TextSwitcher - 文字转换器控件(改变文字时增加一些动画效果) Gallery - 缩略图浏览器控件 ImageSwitcher - 图片转换器控件(改变图片时增加一些动画效果) GridView - 网格控件 ListView - 列表控件 ExpandableList - 支持展开/收缩功能的列表控件

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1、TextSwitcher 的 Demo

textswitcher.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<Button android:id="@+id/btnChange" android:layout_width="wrap_content"

android:layout_height="wrap_content" android:text="改变文字" />

<!--

TextSwitcher - 文字转换器控件(改变文字时增加一些动画效果) -->

<TextSwitcher android:id="@+id/textSwitcher"

android:layout_width="fill_parent" android:layout_height="wrap_content" />

</LinearLayout>

_TextSwitcher.java

代码

package com.webabcd.view;

import java.util.Random;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.view.animation.Animation;

import android.view.animation.AnimationUtils;

import android.widget.Button;

import android.widget.TextSwitcher;

import android.widget.TextView;

import android.widget.ViewSwitcher;

public class _TextSwitcher extends Activity implements ViewSwitcher.ViewFactory {

68

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.textswithcer);

setTitle("TextSwithcer");

final TextSwitcher switcher = (TextSwitcher) findViewById(R.id.textSwitcher);

// 指定转换器的 ViewSwitcher.ViewFactory

switcher.setFactory(this);

// 设置淡入和淡出的动画效果

Animation in = AnimationUtils.loadAnimation(this, android.R.anim.fade_in);

Animation out = AnimationUtils.loadAnimation(this, android.R.anim.fade_out);

switcher.setInAnimation(in);

switcher.setOutAnimation(out);

// 单击一次按钮改变一次文字

Button btnChange = (Button) this.findViewById(R.id.btnChange); btnChange.setOnClickListener(new View.OnClickListener() { @Override

public void onClick(View v) {

switcher.setText(String.valueOf(new Random().nextInt()));

}

});

}

// 重写 ViewSwitcher.ViewFactory 的 makeView(),返回一个 View @Override

public View makeView() {

TextView textView = new TextView(this);

textView.setTextSize(36);

return textView;

}

}

2、Gallery 的 Demo

gallery.xml

69

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<!--

Gallery - 缩略图浏览器控件

spacing - 缩略图列表中各个缩略图之间的间距

-->

<Gallery android:id="@+id/gallery" android:layout_width="fill_parent"

android:layout_height="wrap_content" android:spacing="20px" />

</LinearLayout>

_Gallery.java

代码

package com.webabcd.view;

import android.app.Activity;

import android.content.Context;

import android.os.Bundle;

import android.view.View;

import android.view.ViewGroup;

import android.widget.AdapterView;

import android.widget.BaseAdapter;

import android.widget.Gallery;

import android.widget.ImageView;

import android.widget.Toast;

import android.widget.Gallery.LayoutParams;

public class _Gallery extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.gallery);

setTitle("Gallery");

70

Gallery gallery = (Gallery) findViewById(R.id.gallery); // 为缩略图浏览器指定一个适配器

gallery.setAdapter(new ImageAdapter(this));

// 响应 在缩略图列表上选中某个缩略图后的 事件

gallery.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {

@Override

public void onItemSelected(AdapterView<?> parent, View v, int position, long id) {

Toast.makeText(_Gallery.this, String.valueOf(position), Toast.LENGTH_SHORT).show();

}

@Override

public void onNothingSelected(AdapterView<?> arg0) {

}

});

}

// 继承 BaseAdapter 用以实现自定义的图片适配器

public class ImageAdapter extends BaseAdapter {

private Context mContext;

public ImageAdapter(Context context) {

mContext = context;

}

public int getCount() {

return mThumbIds.length;

}

public Object getItem(int position) {

return position;

}

public long getItemId(int position) {

return position;

}

public View getView(int position, View convertView, ViewGroup parent) {

ImageView image = new ImageView(mContext);

71

image.setImageResource(mThumbIds[position]);

image.setAdjustViewBounds(true);

image.setLayoutParams(new Gallery.LayoutParams(

LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));

return image;

}

}

// 需要显示的图片集合

private Integer[] mThumbIds = { R.drawable.icon01, R.drawable.icon02,

R.drawable.icon03, R.drawable.icon04, R.drawable.icon05 }; }

3、ImageSwitcher 的 Demo

imageswitcher.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">

<Gallery android:id="@+id/gallery" android:layout_width="fill_parent"

android:layout_height="wrap_content" android:spacing="20px" />

<!--

ImageSwitcher - 图片转换器控件(改变图片时增加一些动画效果) -->

<ImageSwitcher android:id="@+id/imageSwitcher"

android:layout_width="fill_parent" android:layout_height="wrap_content" />

</LinearLayout>

_ImageSwitcher.java

代码

72

package com.webabcd.view;

import android.app.Activity;

import android.content.Context;

import android.os.Bundle;

import android.view.View;

import android.view.ViewGroup;

import android.view.animation.AnimationUtils;

import android.widget.AdapterView;

import android.widget.BaseAdapter;

import android.widget.Gallery;

import android.widget.ImageSwitcher;

import android.widget.ImageView;

import android.widget.ViewSwitcher;

import android.widget.Gallery.LayoutParams;

// 图片转换器的使用基本同文字转换器

// 以下是一个用 ImageSwitcher + Gallery 实现的经典的图片浏览器的 Demo public class _ImageSwitcher extends Activity implements

ViewSwitcher.ViewFactory {

private ImageSwitcher mSwitcher;

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.imageswithcer);

setTitle("ImageSwithcer");

mSwitcher = (ImageSwitcher) findViewById(R.id.imageSwitcher); mSwitcher.setFactory(this);

mSwitcher.setInAnimation(AnimationUtils.loadAnimation(this, android.R.anim.fade_in));

mSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this, android.R.anim.fade_out));

Gallery gallery = (Gallery) findViewById(R.id.gallery); gallery.setAdapter(new ImageAdapter(this));

gallery.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {

@Override

public void onItemSelected(AdapterView<?> parent, View v,

73

int position, long id) {

mSwitcher.setImageResource(mImageIds[position]); }

@Override

public void onNothingSelected(AdapterView<?> arg0) {

}

});

}

public class ImageAdapter extends BaseAdapter {

private Context mContext;

public ImageAdapter(Context context) {

mContext = context;

}

public int getCount() {

return mThumbIds.length;

}

public Object getItem(int position) {

return position;

}

public long getItemId(int position) {

return position;

}

public View getView(int position, View convertView, ViewGroup parent) {

ImageView image = new ImageView(mContext);

image.setImageResource(mThumbIds[position]);

image.setAdjustViewBounds(true);

image.setLayoutParams(new Gallery.LayoutParams(

LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));

return image;

}

}

74

private Integer[] mThumbIds = { R.drawable.icon01, R.drawable.icon02,

R.drawable.icon03, R.drawable.icon04, R.drawable.icon05 };

private Integer[] mImageIds = { R.drawable.icon01, R.drawable.icon02,

R.drawable.icon03, R.drawable.icon04, R.drawable.icon05 };

@Override

public View makeView() {

ImageView image = new ImageView(this);

image.setMinimumHeight(200);

image.setMinimumWidth(200);

image.setScaleType(ImageView.ScaleType.FIT_CENTER);

image.setLayoutParams(new ImageSwitcher.LayoutParams(

LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT)); return image;

}

}

4、GridView 的 Demo

gridview.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<!--

GridView - 网格控件

numColumns="auto_fit" - 列数自适应

stretchMode - 缩放模式(stretchMode="columnWidth" - 缩放与列宽大小同步)

-->

<GridView xmlns:android="/apk/res/android" android:id="@+id/gridView" android:layout_width="fill_parent" android:layout_height="fill_parent" android:padding="10px"

android:verticalSpacing="10px" android:horizontalSpacing="10px" android:numColumns="auto_fit" android:columnWidth="60px"

android:stretchMode="columnWidth" android:gravity="center"> </GridView>

_GridView.java

代码

75

package com.webabcd.view;

import android.app.Activity;

import android.content.Context;

import android.os.Bundle;

import android.view.View;

import android.view.ViewGroup;

import android.widget.BaseAdapter;

import android.widget.GridView;

import android.widget.ImageView;

public class _GridView extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

this.setContentView(R.layout.gridview);

setTitle("GridView");

GridView gridView = (GridView) findViewById(R.id.gridView); // 指定网格控件的适配器为自定义的图片适配器

gridView.setAdapter(new ImageAdapter(this));

}

// 自定义的图片适配器

public class ImageAdapter extends BaseAdapter {

private Context mContext;

public ImageAdapter(Context context) {

mContext = context;

}

public int getCount() {

return mThumbIds.length;

}

public Object getItem(int position) {

return position;

}

public long getItemId(int position) {

76

return position;

}

public View getView(int position, View convertView, ViewGroup parent) {

ImageView imageView;

if (convertView == null) {

imageView = new ImageView(mContext);

imageView.setLayoutParams(new GridView.LayoutParams(48, 48));

imageView.setAdjustViewBounds(false);

imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);

imageView.setPadding(5, 5, 5, 5);

} else {

imageView = (ImageView) convertView;

}

imageView.setImageResource(mThumbIds[position]);

return imageView;

}

// 网格控件所需图片数据的数据源

private Integer[] mThumbIds = { R.drawable.icon01, R.drawable.icon02,

R.drawable.icon03, R.drawable.icon04, R.drawable.icon05 };

}

}

5、ListView 的 Demo

main_list_adapter.xml

代码

<?xml version="1.0" encoding="utf-8"?>

<!--

自定义列表适配器的 layout

-->

<LinearLayout xmlns:android="/apk/res/android"

android:orientation="horizontal" android:layout_width="fill_parent"

android:layout_height="fill_parent">

77

<TextView android:id="@+id/text" android:layout_width="wrap_content"

android:layout_height="wrap_content" android:textSize="16sp"> </TextView>

</LinearLayout>

MainListAdapter.java

代码

package com.webabcd.view;

import java.util.List;

import android.content.Context;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.BaseAdapter;

import android.widget.TextView;

// 继承 BaseAdapter 以实现自定义的列表适配器

public class MainListAdapter extends BaseAdapter {

private LayoutInflater mInflater;

private List<String> mData;

public MainListAdapter(Context context, List<String> data) { mInflater = LayoutInflater.from(context);

mData = data;

}

@Override

public int getCount() {

return mData.size();

}

@Override

public Object getItem(int position) {

return mData.get(position);

}

@Override

public long getItemId(int position) {

78

return position;

}

@Override

public View getView(int position, View convertView, ViewGroup parent) {

TextView text;

if (convertView == null) {

// 指定一个 layout 作为自定义列表适配器的 layout

convertView = mInflater.inflate(R.layout.main_list_adapter, null);

text = (TextView) convertView.findViewById(R.id.text); convertView.setTag(text);

} else {

text = (TextView) convertView.getTag();

}

String mItem = mData.get(position);

text.setText(mItem);

return convertView;

}

}

Main.java

代码

package com.webabcd.view;

import java.util.ArrayList;

import java.util.List;

import android.app.ListActivity;

import android.content.Intent;

import android.os.Bundle;

import android.view.View;

import android.widget.ListView;

// 此处要继承 ListActivity ,用以实现 ListView 的功能

public class Main extends ListActivity {

private List<String> mData;

79

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setTheme(android.R.style.Theme_Light);

setContentView(R.layout.main);

mData = getData();

// 使用自定义的列表适配器来展现数据

MainListAdapter adapter = new MainListAdapter(this, mData);

// 如需使用系统内置的列表适配器,则可以使用类似如下的方法 // ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_expandable_list_item_1, mData);

this.setListAdapter(adapter);

}

// ListView 的数据源

private List<String> getData() {

List<String> items = new ArrayList<String>();

items.add("TextView");

items.add("Button");

items.add("ImageButton");

items.add("ImageView");

items.add("CheckBox");

items.add("RadioButton");

items.add("AnalogClock");

items.add("DigitalClock");

items.add("DatePicker");

items.add("TimePicker");

items.add("ToggleButton");

items.add("EditText");

items.add("ProgressBar");

items.add("SeekBar");

items.add("AutoCompleteTextView");

items.add("MultiAutoCompleteTextView");

items.add("ZoomControls");

items.add("Include");

items.add("VideoView");

items.add("WebView");

items.add("RatingBar");

80

items.add("Tab");

items.add("Spinner");

items.add("Chronometer");

items.add("ScrollView");

items.add("TextSwitcher");

items.add("ListView");

items.add("Gallery");

items.add("ImageSwitcher");

items.add("GridView");

items.add("ExpandableList");

return items;

}

// ListView 中某项被选中后的逻辑

@Override

protected void onListItemClick(ListView l, View v, int position, long id) {

Intent intent = new Intent();

intent.setClassName(this, "com.webabcd.view._" + mData.get(position));

startActivityForResult(intent, 0);

}

}

6、ExpandableList 的 Demo

_ExpandableList.java 代码

package com.webabcd.view;

import android.app.ExpandableListActivity;

import android.os.Bundle;

import android.view.ContextMenu;

import android.view.Gravity;

import android.view.MenuItem;

import android.view.View;

import android.view.ViewGroup;

import android.view.ContextMenu.ContextMenuInfo;

import android.widget.AbsListView;

import android.widget.BaseExpandableListAdapter;

import android.widget.ExpandableListAdapter;

import android.widget.ExpandableListView;

81

import android.widget.TextView;

import android.widget.Toast;

import android.widget.ExpandableListView.ExpandableListContextMenuInfo;

// ExpandableList - 可展开/收缩列表

// 继承 ExpandableListActivity 以实现列表的可展开/收缩的功能

public class _ExpandableList extends ExpandableListActivity {

private ExpandableListAdapter mAdapter;

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

setTitle("ExpandableList");

mAdapter = new MyExpandableListAdapter();

setListAdapter(mAdapter);

registerForContextMenu(this.getExpandableListView()); }

// 为列表的每一项创建上下文菜单(即长按后呼出的菜单)

@Override

public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {

menu.setHeaderTitle("ContextMenu"); menu.add(0, 0, 0, "ContextMenu");

}

// 单击上下文菜单后的逻辑

@Override

public boolean onContextItemSelected(MenuItem item) {

ExpandableListContextMenuInfo info = (ExpandableListContextMenuInfo) item.getMenuInfo();

String title = ((TextView) info.targetView).getText().toString();

int type = ExpandableListView.getPackedPositionType(info.packedPosition);

if (type == ExpandableListView.PACKED_POSITION_TYPE_CHILD) { int groupPos = ExpandableListView.getPackedPositionGroup(info.packedPosition);

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int childPos = ExpandableListView.getPackedPositionChild(info.packedPosition);

Toast.makeText(this, title + " - Group Index: " + groupPos + " Child Index: " + childPos, Toast.LENGTH_SHORT).show();

return true;

} else if (type == ExpandableListView.PACKED_POSITION_TYPE_GROUP) {

int groupPos = ExpandableListView.getPackedPositionGroup(info.packedPosition);

Toast.makeText(this, title + " - Group Index: " + groupPos, Toast.LENGTH_SHORT).show();

return true;

}

return false;

}

public class MyExpandableListAdapter extends BaseExpandableListAdapter {

// 父列表数据

private String[] groups =

{

"group1",

"group2",

"group3",

"group4"

};

// 子列表数据

private String[][] children =

{

{ "child1" },

{ "child1", "child2" },

{ "child1", "child2", "child3" },

{ "child1", "child2", "child3", "child4" }

};

@Override

public Object getChild(int groupPosition, int childPosition) {

return children[groupPosition][childPosition];

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}

@Override

public long getChildId(int groupPosition, int childPosition) {

return childPosition;

}

@Override

public int getChildrenCount(int groupPosition) {

return children[groupPosition].length;

}

// 取子列表中的某一项的 View

@Override

public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {

TextView textView = getGenericView();

textView.setText(getChild(groupPosition, childPosition).toString());

return textView;

}

@Override

public Object getGroup(int groupPosition) {

return groups[groupPosition]; }

@Override

public int getGroupCount() {

return groups.length;

}

@Override public long getGroupId(int groupPosition) {

return groupPosition;

}

// 取父列表中的某一项的 View

@Override

public View getGroupView(int groupPosition, boolean isExpanded,

View convertView, ViewGroup parent) {

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TextView textView = getGenericView();

textView.setText(getGroup(groupPosition).toString()); return textView;

}

@Override

public boolean hasStableIds() {

return true;

}

@Override

public boolean isChildSelectable(int groupPosition, int childPosition) {

return true;

}

// 获取某一项的 View 的逻辑

private TextView getGenericView() {

AbsListView.LayoutParams lp = new AbsListView.LayoutParams(

ViewGroup.LayoutParams.FILL_PARENT, 48);

TextView textView = new TextView(_ExpandableList.this); textView.setLayoutParams(lp);

textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);

textView.setPadding(32, 0, 0, 0);

return textView;

}

}

}

Android(9) - 数据库支持(SQLite), 内容提供器

(ContentProvider)

介绍

在 Android 中使用 SQLite, ContentProvider

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?

? 数据库支持(SQLite) - Android 开发平台提供了操作 SQLite 数据库的相关 API 内容提供器(ContentProvider) - 当数据需要在应用程序之间共享时,可以在某程序中使用

ContentProvider 定义 URI, 以使其它应用程序可以通过此 URI 访问指定的数据

1、SQLite 的 Demo

DatabaseHelper.java 代码

package com.webabcd.SQLite;

import android.content.Context;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteOpenHelper;

import android.database.sqlite.SQLiteDatabase.CursorFactory;

// 数据库操作的 Helper 类

public class DatabaseHelper extends SQLiteOpenHelper {

DatabaseHelper(Context context, String name, CursorFactory cursorFactory, int version) {

super(context, name, cursorFactory, version);

}

@Override

public void onCreate(SQLiteDatabase db) {

// TODO 创建数据库后,对数据库的操作

}

@Override

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

// TODO 更改数据库版本的操作

}

@Override

public void onOpen(SQLiteDatabase db) {

super.onOpen(db);

// TODO 每次成功打开数据库后首先被执行

}

}

Main.java

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代码

package com.webabcd.SQLite;

import java.util.Random;

import android.app.Activity;

import android.content.ContentValues;

import android.database.Cursor;

import android.database.SQLException;

import android.database.sqlite.SQLiteDatabase;

import android.os.Bundle;

import android.view.View;

import android.widget.Button;

import android.widget.TextView;

public class Main extends Activity {

private DatabaseHelper dbHelper;

private static final String DATABASE_NAME = "db.db"; private static final int DATABASE_VERSION = 1;

private static final String TABLE_NAME = "employee";

TextView txtMsg;

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

dbHelper = new DatabaseHelper(this, DATABASE_NAME, null, DATABASE_VERSION);

txtMsg = (TextView) this.findViewById(R.id.txtMsg);

Button btn1 = (Button) this.findViewById(R.id.btn1); btn1.setText("创建表");

btn1.setOnClickListener(new Button.OnClickListener() { public void onClick(View v) {

CreateTable();

}

});

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Button btn2 = (Button) this.findViewById(R.id.btn2); btn2.setText("插入 3 条记录");

btn2.setOnClickListener(new Button.OnClickListener() { public void onClick(View v) {

insertItem();

}

});

Button btn3 = (Button) this.findViewById(R.id.btn3); btn3.setText("删除全部记录");

btn3.setOnClickListener(new Button.OnClickListener() { public void onClick(View v) {

deleteItem();

}

});

Button btn4 = (Button) this.findViewById(R.id.btn4); btn4.setText("更新指定数据");

btn4.setOnClickListener(new Button.OnClickListener() { public void onClick(View v) {

updateItem();

}

});

Button btn5 = (Button) this.findViewById(R.id.btn5); btn5.setText("显示全部数据");

btn5.setOnClickListener(new Button.OnClickListener() { public void onClick(View v) {

showItems();

}

});

Button btn6 = (Button) this.findViewById(R.id.btn6); btn6.setText("删除表");

btn6.setOnClickListener(new Button.OnClickListener() { public void onClick(View v) {

dropTable();

}

});

}

// 创建数据表

private void CreateTable() {

SQLiteDatabase db = dbHelper.getWritableDatabase();

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String sql = "CREATE TABLE IF NOT EXISTS " + TABLE_NAME

+ " (ID INTEGER PRIMARY KEY, Name VARCHAR, Age INTEGER);"; try {

db.execSQL(sql);

txtMsg.append("数据表成功创建\n");

} catch (SQLException ex) {

txtMsg.append("数据表创建错误\n" + ex.toString() + "\n"); }

}

// 插入数据

private void insertItem() {

SQLiteDatabase db = dbHelper.getWritableDatabase();

try {

Random random = new Random();

for (int i = 0; i < 3; i++) {

String sql = "insert into " + TABLE_NAME

+ " (name, age) values ('name" + String.valueOf(i) + "', " + random.nextInt() + ")";

// execSQL() - 执行指定的 sql

db.execSQL(sql);

}

txtMsg.append("成功插入 3 条数据\n");

} catch (SQLException ex) {

txtMsg.append("插入数据失败\n" + ex.toString() + "\n");

}

}

// 删除数据

private void deleteItem() {

try {

SQLiteDatabase db = dbHelper.getWritableDatabase();

db.delete(TABLE_NAME, " id < 999999", null);

txtMsg.append("成功删除数据\n");

} catch (SQLException e) {

txtMsg.append("删除数据失败\n");

}

}

// 更新数据

private void updateItem() {

SQLiteDatabase db = dbHelper.getWritableDatabase();

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try {

ContentValues values = new ContentValues();

values.put("name", "批量更新后的名字");

db.update(TABLE_NAME, values, "id<?", new String[] { "3" }); txtMsg.append("成功更新数据\n");

} catch (SQLException e) {

txtMsg.append("更新数据失败\n");

}

}

// 查询数据

private void showItems() {

SQLiteDatabase db = dbHelper.getReadableDatabase();

try {

String[] column = { "id", "name", "age" };

Cursor cursor = db.query(TABLE_NAME, column, null, null, null, null, null);

Integer num = cursor.getCount();

txtMsg.append("共 " + Integer.toString(num) + " 条记录\n"); cursor.moveToFirst();

while (cursor.getPosition() != cursor.getCount()) {

txtMsg.append(Integer.toString(cursor.getPosition()) + "," + String.valueOf(cursor.getString(0)) + "," + cursor.getString(1) + ","

+ String.valueOf(cursor.getString(2)) + "\n"); cursor.moveToNext();

}

} catch (SQLException ex) {

txtMsg.append("读取数据失败\n" + ex.toString() + "\n");

}

}

// 删除数据表

private void dropTable() {

SQLiteDatabase db = dbHelper.getWritableDatabase();

String sql = "DROP TABLE IF EXISTS " + TABLE_NAME;

try {

db.execSQL(sql);

txtMsg.append("数据表删除成功\n");

} catch (SQLException ex) {

txtMsg.append("数据表删除错误\n" + ex.toString() + "\n");

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}

}

}

2、ContentProvider 的 Demo

MyUser.java 代码

package com.webabcd.contentprovider;

import android.net.Uri;

import android.provider.BaseColumns;

// 自定义 ContentProvider 所需的实体类

public class MyUser {

// 必须要有 _id 字段。本例中 BaseColumn 类中已经包含了 _id 字段

public static final class User implements BaseColumns {

// 定义 CONTENT_URI

public static final Uri CONTENT_URI = Uri.parse("content://com.webabcd.MyContentProvider");

// 表数据列

public static final String USER_NAME = "USER_NAME";

}

}

MyContentProvider.java

代码

package com.webabcd.contentprovider;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import org.apache.http.util.EncodingUtils;

import android.content.ContentProvider;

import android.content.ContentUris;

import android.content.ContentValues;

import android.database.Cursor;

import android.database.MatrixCursor;

import android.net.Uri;

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// 继承 ContentProvider 以实现自定义的 ContentProvider(基于文件的信息存储) public class MyContentProvider extends ContentProvider {

private File file;

private FileOutputStream out;

private FileInputStream in;

// ContentProvider 的删除数据接口

@Override

public int delete(Uri uri, String selection, String[] selectionArgs) { // TODO Auto-generated method stub

return 0;

}

@Override

public String getType(Uri uri) {

// TODO Auto-generated method stub

return null;

}

// ContentProvider 的插入数据接口

@Override

public Uri insert(Uri uri, ContentValues values) {

try {

out = new FileOutputStream(file);

out.write(values.getAsString(MyUser.User.USER_NAME).getBytes()); out.close();

int rowId = 0;

Uri rowUri = ContentUris.appendId(

MyUser.User.CONTENT_URI.buildUpon(), rowId).build(); getContext().getContentResolver().notifyChange(rowUri, null);

return rowUri;

} catch (Exception e) {

return null;

}

}

// 创建用于保存信息的文件

@Override

public boolean onCreate() {

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try {

// 每个包中应用程序的私有目录为:/data/data/包名/

// SD 卡目录为:/sdcard

file = new File("/data/data/com.webabcd.contentprovider/", "demo.txt");

if (!file.exists())

file.createNewFile();

return true;

} catch (Exception ex) {

return false;

}

}

// ContentProvider 的查询数据接口

@Override

public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {

String content;

try {

in = new FileInputStream(file);

int length = (int) file.length();

byte[] buffer = new byte[length];

in.read(buffer, 0, length);

content = EncodingUtils.getString(buffer, "UTF-8");

in.close();

String[] columns = new String[] { MyUser.User._ID, MyUser.User.USER_NAME };

MatrixCursor cur = new MatrixCursor(columns);

String[] values = new String[] { "0", content };

cur.moveToFirst();

cur.addRow(values);

return cur;

} catch (Exception e) {

return null;

}

}

// ContentProvider 的更新数据接口

@Override

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public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {

// TODO Auto-generated method stub

return 0;

}

}

Main.java 代码

package com.webabcd.contentprovider;

import java.util.Random;

import android.app.Activity;

import android.content.ContentUris;

import android.content.ContentValues;

import android.database.Cursor;

import android.net.Uri;

import android.os.Bundle;

import android.provider.Contacts;

import android.provider.Contacts.People;

import android.util.Log;

import android.view.View;

import android.widget.Button;

import android.widget.Toast;

/*

* 几个常用的系统内置的 ContentProvider 如下:

* content://media/internal/images 这个URI将返回设备上存储的所有图片

* content://contacts/people/ 这个URI将返回设备上的所有联系人信息

* content://contacts/people/45 这个URI返回单个结果(联系人信息中ID为45的联系人记录)

*/

public class Main extends Activity {

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

Button btn1 = (Button) this.findViewById(R.id.btn1);

btn1.setText("新增联系人记录");

btn1.setOnClickListener(new Button.OnClickListener() {

public void onClick(View v) {

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Random random = new Random();

insertRecords("name" + String.valueOf(random.nextInt()), String

.valueOf(random.nextInt()));

}

});

Button btn2 = (Button) this.findViewById(R.id.btn2);

btn2.setText("查看联系人记录");

btn2.setOnClickListener(new Button.OnClickListener() {

public void onClick(View v) {

displayRecords();

}

});

Button btn3 = (Button) this.findViewById(R.id.btn3);

btn3.setText("清除联系人记录");

btn3.setOnClickListener(new Button.OnClickListener() {

public void onClick(View v) {

deleteRecords();

}

});

Button btn4 = (Button) this.findViewById(R.id.btn4);

btn4.setText("更新联系人记录");

btn4.setOnClickListener(new Button.OnClickListener() {

public void onClick(View v) {

// 此处只是演示,id 来自 People._ID ,可参见 displayRecords() 是如何获取 id 的

int id = 0;

updateRecord(id, "修改后的name");

}

});

Button btn5 = (Button) this.findViewById(R.id.btn5);

btn5.setText("新增记录到 MyContentProvider");

btn5.setOnClickListener(new Button.OnClickListener() {

public void onClick(View v) {

insertRecord2MyContentProvider("webabcd");

}

});

Button btn6 = (Button) this.findViewById(R.id.btn6);

btn6.setText("获取记录从 MyContentProvider");

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btn6.setOnClickListener(new Button.OnClickListener() {

public void onClick(View v) {

displayRecord2MyContentProvider();

}

});

}

// 调用 ContentProvider 的插入接口

private void insertRecords(String name, String phoneNum) {

ContentValues values = new ContentValues();

values.put(People.NAME, name);

Uri uri = getContentResolver().insert(People.CONTENT_URI, values); Log.d("MyDebug", uri.toString());

Uri numberUri = Uri.withAppendedPath(uri,

People.Phones.CONTENT_DIRECTORY);

Log.d("MyDebug", numberUri.toString());

values.clear();

values.put(Contacts.Phones.TYPE, People.Phones.TYPE_MOBILE); values.put(People.NUMBER, phoneNum);

getContentResolver().insert(numberUri, values);

}

// 调用 ContentProvider 的查询接口

private void displayRecords() {

String[] columns = new String[] { People._ID, People.NAME,

People.NUMBER };

Uri contacts = People.CONTENT_URI;

Log.d("MyDebug", contacts.toString());

Cursor cur = managedQuery(contacts, columns, // 要返回的数据字段 null, // WHERE子句

null, // WHERE 子句的参数

null // Order-by子句

);

if (cur.moveToFirst()) {

String id = null;

String name = null;

String phoneNo = null;

while (cur.getPosition() != cur.getCount()) {

id = cur.getString(cur.getColumnIndex(People._ID)); name = cur.getString(cur.getColumnIndex(People.NAME));

phoneNo = cur.getString(cur.getColumnIndex(People.NUMBER));

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Toast.makeText(this, id + " / " + name + " / " + phoneNo, Toast.LENGTH_SHORT).show();

cur.moveToNext();

}

}

}

// 调用 ContentProvider 的删除接口

private void deleteRecords() {

Uri uri = People.CONTENT_URI;

Log.d("MyDebug", uri.toString());

getContentResolver().delete(uri, null, null);

// getContentResolver().delete(uri, "NAME=" + "'name'", null); }

// 调用 ContentProvider 的更新接口

private void updateRecord(int recordNo, String name) {

Uri uri = ContentUris.withAppendedId(People.CONTENT_URI, recordNo); Log.d("MyDebug", uri.toString());

ContentValues values = new ContentValues();

values.put(People.NAME, name);

getContentResolver().update(uri, values, null, null);

}

// 调用自定义 ContentProvider 的插入接口

private void insertRecord2MyContentProvider(String name) {

ContentValues values = new ContentValues();

values.put(MyUser.User.USER_NAME, name);

getContentResolver().insert(MyUser.User.CONTENT_URI, values);

}

// 调用自定义 ContentProvider 的查询接口

private void displayRecord2MyContentProvider() {

String[] columns = new String[] { MyUser.User.USER_NAME };

Uri uri = MyUser.User.CONTENT_URI;

Cursor cur = managedQuery(uri, columns, null, null, null);

while (cur.getPosition() != cur.getCount()) {

String id = cur.getString(cur.getColumnIndex(People._ID));

String name = cur.getString(cur.getColumnIndex(MyUser.User.USER_NAME));

Toast.makeText(this,

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id + " / " + name,

Toast.LENGTH_SHORT).show();

cur.moveToNext();

}

}

}

AndroidManifest.xml 代码

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="/apk/res/android" package="com.webabcd.contentprovider"

android:versionCode="1"

android:versionName="1.0">

<application android:icon="@drawable/icon" android:label="@string/app_name">

<activity android:name=".Main"

android:label="@string/app_name">

<intent-filter>

<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" /> </intent-filter>

</activity>

<!--

配置一个自定义的 ContentProvider"

-->

<provider android:name="MyContentProvider" android:authorities="com.webabcd.MyContentProvider" />

</application>

<uses-permission android:name="android.permission.WRITE_CONTACTS"></uses-permission>

<uses-permission android:name="android.permission.READ_CONTACTS"></uses-permission>

<uses-sdk android:minSdkVersion="3" />

</manifest>

Android(10) - HTTP 通信, XML 解析, 通过 Hander 实现异步

消息处理

98

介绍

在 Android 中与服务端做 HTTP 通信,解析 XML,通过 Handler 实现异步消息处理

?

?

?

HTTP 通信 - 与服务端做 HTTP 通信,分别以 GET 方式和 POST 方式做演示 XML 解析 - 可以用两种方式解析 XML,分别是 DOM 方式和 SAX 方式 异步消息处理 - 通过 Handler 实现异步消息处理,以一个自定义的异步下载类来说明 Handler 的用法

1、HTTP 通信和 XML 解析的 Demo

MySAXHandler.java

代码

package munication;

import org.xml.sax.Attributes;

import org.xml.sax.SAXException;

import org.xml.sax.helpers.DefaultHandler;

// 继承 DefaultHandler 以实现指定 XML 的 SAX 解析器

// DOM - W3C 标准,需要把 xml 数据全部加载完成后才能对其做解析,可对树做任意遍历 // SAX - 流式解析,通过事件模型解析 xml,只能顺序解析

public class MySAXHandler extends DefaultHandler {

private boolean mIsTitleTag = false;

private boolean mIsSalaryTag = false;

private boolean mIsBirthTag = false;

private String mResult = "";

// 打开 xml 文档的回调函数

@Override

public void startDocument() throws SAXException {

// TODO Auto-generated method stub

super.startDocument();

}

// 关闭 xml 文档的回调函数

@Override

public void endDocument() throws SAXException {

// TODO Auto-generated method stub

super.endDocument();

}

// 一发现元素开始标记就回调此函数

@Override

public void startElement(String uri, String localName, String qName,

99

Attributes attributes) throws SAXException {

if (localName == "title")

mIsTitleTag = true;

else if (localName == "salary")

mIsSalaryTag = true;

else if (localName == "dateOfBirth")

mIsBirthTag = true;

else if (localName == "employee")

mResult += "\nname:" + attributes.getValue("name"); }

// 一发现元素结束标记就回调此函数

@Override

public void endElement(String uri, String localName, String qName) throws SAXException {

if (localName == "title")

mIsTitleTag = false;

else if (localName == "salary")

mIsSalaryTag = false;

else if (localName == "dateOfBirth")

mIsBirthTag = false;

}

// 一发现元素值或属性值就回调此函数

@Override

public void characters(char[] ch, int start, int length)

throws SAXException {

if (mIsTitleTag)

mResult += new String(ch, start, length);

else if (mIsSalaryTag)

mResult += " salary:" + new String(ch, start, length); else if (mIsBirthTag)

mResult += " dateOfBirth:" + new String(ch, start, length); }

public String getResult(){

return mResult;

}

}

Main.java

代码

package munication;

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import java.io.BufferedInputStream;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.net.HttpURLConnection;

import java.net.URL;

import java.net.URLConnection;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.Map;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.parsers.SAXParser;

import javax.xml.parsers.SAXParserFactory;

import org.apache.http.HttpEntity;

import org.apache.http.HttpResponse;

import org.apache.http.client.entity.UrlEncodedFormEntity; import org.apache.http.client.methods.HttpPost;

import org.apache.http.impl.client.DefaultHttpClient; import org.apache.http.message.BasicNameValuePair; import org.apache.http.protocol.HTTP;

import org.apache.http.util.ByteArrayBuffer;

import org.apache.http.util.EncodingUtils;

import org.w3c.dom.Document;

import org.w3c.dom.Element;

import org.w3c.dom.NodeList;

import org.xml.sax.InputSource;

import org.xml.sax.XMLReader;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.widget.Button;

import android.widget.TextView;

public class Main extends Activity {

private TextView textView;

/** Called when the activity is first created. */ @Override

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public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

textView = (TextView) this.findViewById(R.id.textView);

Button btn1 = (Button) this.findViewById(R.id.btn1); btn1.setText("http get demo");

btn1.setOnClickListener(new Button.OnClickListener() { public void onClick(View v) {

httpGetDemo();

}

});

Button btn2 = (Button) this.findViewById(R.id.btn2); btn2.setText("http post demo");

btn2.setOnClickListener(new Button.OnClickListener() { public void onClick(View v) {

httpPostDemo();

}

});

Button btn3 = (Button) this.findViewById(R.id.btn3); // DOM - Document Object Model

btn3.setText("DOM 解析 XML");

btn3.setOnClickListener(new Button.OnClickListener() { public void onClick(View v) {

DOMDemo();

}

});

Button btn4 = (Button) this.findViewById(R.id.btn4); // SAX - Simple API for XML

btn4.setText("SAX 解析 XML");

btn4.setOnClickListener(new Button.OnClickListener() { public void onClick(View v) {

SAXDemo();

}

});

}

// Android 调用 http 协议的 get 方法

// 本例:以 http 协议的 get 方法获取远程页面响应的内容

private void httpGetDemo(){

102

try {

// 模拟器测试时,请使用外网地址

URL url = new URL("http://xxx.xxx.xxx");

URLConnection con = url.openConnection();

String result = "http status code: " + ((HttpURLConnection)con).getResponseCode() + "\n";

// HttpURLConnection.HTTP_OK

InputStream is = con.getInputStream();

BufferedInputStream bis = new BufferedInputStream(is);

ByteArrayBuffer bab = new ByteArrayBuffer(32);

int current = 0;

while ( (current = bis.read()) != -1 ){

bab.append((byte)current);

}

result += EncodingUtils.getString(bab.toByteArray(), HTTP.UTF_8);

bis.close();

is.close();

textView.setText(result);

} catch (Exception e) {

textView.setText(e.toString());

}

}

// Android 调用 http 协议的 post 方法

// 本例:以 http 协议的 post 方法向远程页面传递参数,并获取其响应的内容

private void httpPostDemo(){

try {

// 模拟器测试时,请使用外网地址

String url = "/post.php";

Map<String, String> data = new HashMap<String, String>();

data.put("name", "webabcd");

data.put("salary", "100");

DefaultHttpClient httpClient = new DefaultHttpClient();

HttpPost httpPost = new HttpPost(url);

ArrayList<BasicNameValuePair> postData = new ArrayList<BasicNameValuePair>();

for (Map.Entry<String, String> m : data.entrySet()) {

postData.add(new BasicNameValuePair(m.getKey(), m.getValue

()));

103

}

UrlEncodedFormEntity entity = new UrlEncodedFormEntity(postData, HTTP.UTF_8);

httpPost.setEntity(entity);

HttpResponse response = httpClient.execute(httpPost);

String result = "http status code: " + response.getStatusLine().getStatusCode() + "\n";

// HttpURLConnection.HTTP_OK

HttpEntity httpEntity = response.getEntity();

InputStream is = httpEntity.getContent();

result += convertStreamToString(is);

textView.setText(result);

} catch (Exception e) {

textView.setText(e.toString());

}

}

// 以 DOM 方式解析 XML(xml 数据详见 res/raw/employee.xml)

private void DOMDemo(){

try {

DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();

DocumentBuilder docBuilder = docFactory.newDocumentBuilder(); Document doc = docBuilder.parse(this.getResources().openRawResource(R.raw.employee));

Element rootElement = doc.getDocumentElement();

NodeList employeeNodeList = rootElement.getElementsByTagName("employee");

textView.setText("DOMDemo" + "\n");

String title = rootElement.getElementsByTagName("title").item(0).getFirstChild().getNodeValue();

textView.append(title);

for (int i=0; i<employeeNodeList.getLength(); i++){

Element employeeElement = ((Element)employeeNodeList.item(i));

String name = employeeElement.getAttribute("name");

String salary = employeeElement.getElementsByTagName("salary

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").item(0).getFirstChild().getNodeValue();

String dateOfBirth = employeeElement.getElementsByTagName("dateOfBirth").item(0).getFirstChild().getNodeValue();

textView.append("\nname: "+name+" salary: "+salary+" dateOfBirth: " + dateOfBirth);

}

} catch (Exception e) {

textView.setText(e.toString());

}

}

// 以 SAX 方式解析 XML(xml 数据详见 res/raw/employee.xml)

// SAX 解析器的实现详见 MySAXHandler.java

private void SAXDemo(){

try {

SAXParserFactory saxFactory = SAXParserFactory.newInstance(); SAXParser parser = saxFactory.newSAXParser();

XMLReader reader = parser.getXMLReader();

MySAXHandler handler = new MySAXHandler();

reader.setContentHandler(handler);

reader.parse(new InputSource(this.getResources().openRawResource(R.raw.employee)));

String result = handler.getResult();

textView.setText("SAXDemo" + "\n");

textView.append(result);

} catch (Exception e) {

textView.setText(e.toString());

}

}

// 辅助方法,用于把流转换为字符串

private String convertStreamToString(InputStream is) {

BufferedReader reader = new BufferedReader(new InputStreamReader(is));

StringBuilder sb = new StringBuilder();

String line = null;

try {

while ((line = reader.readLine()) != null) {

sb.append(line + "\n");

}

} catch (IOException e) {

e.printStackTrace();

105

} finally {

try {

is.close();

} catch (IOException e) {

e.printStackTrace();

}

}

return sb.toString();

}

}

2、用 Handler 来实现异步消息处理,以一个可以实时汇报下载进度的异步下载类为例

开发一个 Android 类库,本例中此类库名为 webabcd_util

New -> Java Project

项目上点右键 -> Build Path -> Add Libraries -> User Library -> User Libraries -> New -> 为类库起个名字 -> 选中这个类库 -> Add JARs 导入 Android 的 jar 包

项目上点右键 -> Build Path -> Add Libraries -> User Library -> 选择 Android 库

DownloadManagerAsync.java 代码

package webabcd.util;

import java.io.BufferedReader;

import java.io.File;

import java.io.FileOutputStream;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.net.URL;

import java.net.URLConnection;

import org.apache.http.protocol.HTTP;

import android.os.Handler;

import android.os.Message;

import android.util.Log;

// 以一个实例,即异步下载,来演示 Android 的异步消息处理(用 Handler 的方式)

public class DownloadManagerAsync {

public DownloadManagerAsync() {

106

}

// 实例化自定义的 Handler

EventHandler mHandler = new EventHandler(this);

// 按指定 url 地址下载文件到指定路径

public void download(final String url, final String savePath) {

new Thread(new Runnable() {

public void run() {

try {

sendMessage(FILE_DOWNLOAD_CONNECT);

URL sourceUrl = new URL(url);

URLConnection conn = sourceUrl.openConnection();

InputStream inputStream = conn.getInputStream();

int fileSize = conn.getContentLength();

File savefile = new File(savePath);

if (savefile.exists()) {

savefile.delete();

}

savefile.createNewFile();

FileOutputStream outputStream = new FileOutputStream( savePath, true);

byte[] buffer = new byte[1024];

int readCount = 0;

int readNum = 0;

int prevPercent = 0;

while (readCount < fileSize && readNum != -1) {

readNum = inputStream.read(buffer);

if (readNum > -1) {

outputStream.write(buffer);

readCount = readCount + readNum;

int percent = (int) (readCount * 100 / fileSize); if (percent > prevPercent) {

// 发送下载进度信息

sendMessage(FILE_DOWNLOAD_UPDATE, percent, readCount);

prevPercent = percent;

}

107

}

}

outputStream.close();

sendMessage(FILE_DOWNLOAD_COMPLETE, savePath);

} catch (Exception e) {

sendMessage(FILE_DOWNLOAD_ERROR, e);

Log.e("MyError", e.toString());

}

}

}).start();

}

// 读取指定 url 地址的响应内容

public void download(final String url) {

new Thread(new Runnable() {

public void run() {

try {

sendMessage(FILE_DOWNLOAD_CONNECT);

URL sourceUrl = new URL(url);

URLConnection conn = sourceUrl.openConnection(); conn.setConnectTimeout(3000);

BufferedReader reader = new BufferedReader(

new InputStreamReader(conn.getInputStream(), HTTP.UTF_8));

String line = null;

StringBuffer content = new StringBuffer();

while ((line = reader.readLine()) != null) {

content.append(line);

}

reader.close();

sendMessage(FILE_DOWNLOAD_COMPLETE, content.toString());

} catch (Exception e) {

sendMessage(FILE_DOWNLOAD_ERROR, e);

Log.e("MyError", e.toString());

}

}

}).start();

}

108

// 向 Handler 发送消息

private void sendMessage(int what, Object obj) {

// 构造需要向 Handler 发送的消息

Message msg = mHandler.obtainMessage(what, obj);

// 发送消息

mHandler.sendMessage(msg);

}

private void sendMessage(int what) {

Message msg = mHandler.obtainMessage(what);

mHandler.sendMessage(msg);

}

private void sendMessage(int what, int arg1, int arg2) {

Message msg = mHandler.obtainMessage(what, arg1, arg2);

mHandler.sendMessage(msg);

}

private static final int FILE_DOWNLOAD_CONNECT = 0;

private static final int FILE_DOWNLOAD_UPDATE = 1;

private static final int FILE_DOWNLOAD_COMPLETE = 2;

private static final int FILE_DOWNLOAD_ERROR = -1;

// 自定义的 Handler

private class EventHandler extends Handler {

private DownloadManagerAsync mManager;

public EventHandler(DownloadManagerAsync manager) {

mManager = manager;

}

// 处理接收到的消息

@Override

public void handleMessage(Message msg) {

switch (msg.what) {

case FILE_DOWNLOAD_CONNECT:

if (mOnDownloadConnectListener != null)

mOnDownloadConnectListener.onDownloadConnect(mManager); break;

case FILE_DOWNLOAD_UPDATE:

if (mOnDownloadUpdateListener != null)

mOnDownloadUpdateListener.onDownloadUpdate(mManager,

109

msg.arg1);

break;

case FILE_DOWNLOAD_COMPLETE:

if (mOnDownloadCompleteListener != null)

mOnDownloadCompleteListener.onDownloadComplete(mManager, msg.obj);

break;

case FILE_DOWNLOAD_ERROR:

if (mOnDownloadErrorListener != null)

mOnDownloadErrorListener.onDownloadError(mManager, (Exception) msg.obj);

break;

default:

break;

}

}

}

// 定义连接事件

private OnDownloadConnectListener mOnDownloadConnectListener;

public interface OnDownloadConnectListener {

void onDownloadConnect(DownloadManagerAsync manager);

}

public void setOnDownloadConnectListener(OnDownloadConnectListener listener) {

mOnDownloadConnectListener = listener;

}

// 定义下载进度更新事件

private OnDownloadUpdateListener mOnDownloadUpdateListener;

public interface OnDownloadUpdateListener {

void onDownloadUpdate(DownloadManagerAsync manager, int percent); }

public void setOnDownloadUpdateListener(OnDownloadUpdateListener listener) {

mOnDownloadUpdateListener = listener;

}

// 定义下载完成事件

private OnDownloadCompleteListener mOnDownloadCompleteListener;

public interface OnDownloadCompleteListener {

void onDownloadComplete(DownloadManagerAsync manager, Object result); }

public void setOnDownloadCompleteListener(

110

OnDownloadCompleteListener listener) {

mOnDownloadCompleteListener = listener;

}

// 定义下载异常事件

private OnDownloadErrorListener mOnDownloadErrorListener;

public interface OnDownloadErrorListener {

void onDownloadError(DownloadManagerAsync manager, Exception e); }

public void setOnDownloadErrorListener(OnDownloadErrorListener listener) {

mOnDownloadErrorListener = listener;

}

}

调用上面的自定义的 Android 类库

项目上点右键 -> Properties -> Java Build Path -> Projects -> Add 引用上面的类库

Main.java 代码

package com.webabcd.handler;

import android.app.Activity;

import android.os.Bundle;

import android.widget.TextView;

import webabcd.util.DownloadManagerAsync;

public class Main extends Activity implements

DownloadManagerAsync.OnDownloadCompleteListener,

DownloadManagerAsync.OnDownloadUpdateListener,

DownloadManagerAsync.OnDownloadErrorListener {

TextView txt;

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

DownloadManagerAsync manager = new DownloadManagerAsync(); manager.setOnDownloadCompleteListener(this);

111

manager.setOnDownloadUpdateListener(this);

manager.download("/webabcd/Android.rar", "/sdcard/Android.rar");

Android总结

txt = (TextView) this.findViewById(R.id.txt);

txt.setText("开始下载");

}

public void onDownloadComplete(DownloadManagerAsync manager, Object result) {

txt.setText("下载完成");

}

public void onDownloadUpdate(DownloadManagerAsync manager, int percent) {

txt.setText("下载进度:" + String.valueOf(percent) + "%");

}

public void onDownloadError(DownloadManagerAsync manager, Exception e) {

txt.setText("下载出错");

}

}

OK

[源码下载]

112

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