Android Widget开发案例(伦敦奥运会倒计时!)
河北衡水武强 3月16日20:21

效果图:
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一、新建一个Android工程命名为:WidgetDemo.



二、准备素材，一个是Widget的图标，一个是Widget的背景。存放目录如下图:


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三、修改string.xml文件如下:

<?xml version="1.0" encoding="utf-8"?><resources>    <string name="hello">Hello World, WidetDemo!</string>    <string name="app_name">DaysToWorldCup</string></resources>

四、建立Widget内容提供者文件，我们在res下建立xml文件夹，并且新建一个widget_provider.xml代码入下:

<?xml version="1.0" encoding="utf-8"?><appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"android:minWidth="50dip"android:minHeight="50dip"android:updatePeriodMillis="10000"android:initialLayout="@layout/main"/> 

五、修改main.xml布局，代码如下:

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:background="@drawable/wordcup"    ><TextView  android:id="@+id/wordcup"    android:layout_width="fill_parent"     android:layout_height="wrap_content"     android:text="@string/hello" android:textSize="12px"    android:textColor="#ff0000"    /></LinearLayout>

六、修改WidgetDemo.java代码如下:

package com.android.tutor;import java.util.Calendar;import java.util.Date;import java.util.GregorianCalendar;import java.util.Timer;import java.util.TimerTask;import android.appwidget.AppWidgetManager;import android.appwidget.AppWidgetProvider;import android.content.ComponentName;import android.content.Context;import android.widget.RemoteViews;public class WidetDemo extends AppWidgetProvider {    /** Called when the activity is first created. */  @Overridepublic void onUpdate(Context context, AppWidgetManager appWidgetManager,int[] appWidgetIds) {Timer timer = new Timer();timer.scheduleAtFixedRate(new MyTime(context,appWidgetManager), 1, 60000);super.onUpdate(context, appWidgetManager, appWidgetIds);}private class MyTime extends TimerTask{RemoteViews remoteViews;AppWidgetManager appWidgetManager;ComponentName thisWidget;public MyTime(Context context,AppWidgetManager appWidgetManager){this.appWidgetManager = appWidgetManager;remoteViews = new RemoteViews(context.getPackageName(),R.layout.main);thisWidget = new ComponentName(context,WidetDemo.class);}public void run() {Date date = new Date();Calendar calendar = new GregorianCalendar(2010,06,11);long days = (((calendar.getTimeInMillis()-date.getTime())/1000))/86400;remoteViews.setTextViewText(R.id.wordcup, "距离南非世界杯还有" + days+"天");appWidgetManager.updateAppWidget(thisWidget, remoteViews);}}  }

七、修改配置文件AndroidManifest.xml，代码如下:

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"      package="com.android.tutor"      android:versionCode="1"      android:versionName="1.0">    <application android:icon="@drawable/icon" android:label="@string/app_name">        <receiver android:name=".WidetDemo"                  android:label="@string/app_name">            <intent-filter>                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />            </intent-filter>            <meta-data android:name="android.appwidget.provider"               android:resource="@xml/widget_provider"            />        </receiver>    </application>    <uses-sdk android:minSdkVersion="7" /></manifest> 

八、点击运行(Ctrl+F11),之，运行成功后，我们长时间点击桌面，会出现如下俩个，依次点击，就可以看到最上面的效果图:
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