Android学习笔记_33_Widget时钟（MetaData）

Widgets在文档docs\guide\topics\appwidgets\index.html下

Android中AppWidget的分析与应用：AppWidgetProvider

　　一、在

AndroidManifest.xml文件中配置

Widgets：

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.widget"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />

<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<receiver android:name=".TimeWidgetProvider" >
<intent-filter>
<action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
</intent-filter>
<meta-data
android:name="android.appwidget.provider"
android:resource="@xml/timewidget_info" />
</receiver>
<service android:name=".TimerService"></service>
</application>

</manifest>

　　二、在项目的res目录下建立xml目录，并且创建 timewidget_info.xml 文件，内容如下：

<?xml version="1.0" encoding="UTF-8"?>
<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"
android:initialLayout="@layout/time_appwidget"
android:minHeight="40dp"
android:minWidth="40dp"
android:updatePeriodMillis="0" />

　　三、在layout文件夹下建立文件time_appwidget.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="@drawable/rectangle"
>

<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/textView"
android:text="current time"
/>

</LinearLayout>

　　四、在drawable文件夹下建立rectangle.xml文件(这部可以省略，主要是为了美化TextView控件，渐变效果)：

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle" >

<!-- 设置弧度 -->
<corners android:radius="9dp" />

<gradient
android:angle="270"
android:endColor="#5EADF4"
android:startColor="#B3F0FF" />

<padding
android:bottom="5dp"
android:left="5dp"
android:right="5dp"
android:top="5dp" />

<stroke
android:dashGap="1dp"
android:dashWidth="10dp"
android:width="6dp"
android:color="#0000FF" />

</shape>

　　五、后台代码实现：

package com.example.widget;

import android.appwidget.AppWidgetManager;
import android.appwidget.AppWidgetProvider;
import android.content.Context;
import android.content.Intent;

public class TimeWidgetProvider extends AppWidgetProvider {

@Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager,
int[] appWidgetIds) {
super.onUpdate(context, appWidgetManager, appWidgetIds);
}

//当一个Widgets时会被调用
public void onDeleted(Context context, int[] appWidgetIds) {
// TODO Auto-generated method stub
super.onDeleted(context, appWidgetIds);
}

//第一次往桌面添加Widgets时会被调用，之后添加同类型Widgets不会被调用
public void onEnabled(Context context) {
context.startService(new Intent(context, TimerService.class));
}

//从桌面上删除最后一个Widgets时会被调用
public void onDisabled(Context context) {
context.stopService(new Intent(context, TimerService.class));
}

}

package com.example.widget;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;

import android.annotation.SuppressLint;
import android.app.Service;
import android.appwidget.AppWidgetManager;
import android.content.ComponentName;
import android.content.Intent;
import android.os.IBinder;
import android.widget.RemoteViews;

public class TimerService extends Service {
private Timer timer;

@Override
public void onCreate() {
super.onCreate();
timer = new Timer();
timer.schedule(new MyTimerTask(), 0, 1000);
}
private final class MyTimerTask extends TimerTask{
@SuppressLint("SimpleDateFormat")
@Override
public void run() {
SimpleDateFormat sdf= new SimpleDateFormat("hh:mm:ss");
String time = sdf.format(new Date());
//获取Widgets管理器
AppWidgetManager widgetManager =AppWidgetManager.getInstance(getApplicationContext());
//widgetManager所操作的Widget对应的远程视图即当前Widget的layout文件
RemoteViews remoteView = new RemoteViews(getPackageName(), R.layout.time_appwidget);
remoteView.setTextViewText(R.id.textView, time);
//当点击Widgets时触发的世界
//remoteView.setOnClickPendingIntent(viewId, pendingIntent)
ComponentName componentName = new  ComponentName(getApplicationContext(),TimeWidgetProvider.class);
widgetManager.updateAppWidget(componentName, remoteView);
}
}

@Override
public void onDestroy() {
timer.cancel();
timer=null;
super.onDestroy();
}

@Override
public IBinder onBind(Intent intent) {
return null;
}

}