8.Android Widget开发案例(世界杯倒计时)

今天我们学习Android Widget的开发，由于快凌晨了，我就不说的太具体了，同志们就模仿吧！首先看一下效果图：

下面是Demo的详细步骤：

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：

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. */

    @Override
    public 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)，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：