Android之桌面组件App Widget案例

模拟一个案例：把AppWidget添加到桌面后，点击AppWidget后AppWidget文本会轮回改变

main.xml布局文件

<?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">
    <TextView android:id="@+id/tv"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" 
        android:text="程序入口" 
        android:textSize="50dip"/>
</LinearLayout>

res/xml/my_appwidget.xml布局文件

<?xml version="1.0" encoding="utf-8"?>
<appwidget-provider
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:minWidth="120dp" 
    android:minHeight="60dp"
    android:updatePeriodMillis="1000"
    android:initialLayout="@layout/main">
</appwidget-provider>

清单文件

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

</manifest>

变量类UtilTool：用来控件文本改变

package com.ljq.activity;


public class UtilTool {
    public static boolean isChange=true;
}

TestActivity类，继承自AppWidgetProvider

package com.ljq.activity;

import android.app.PendingIntent;
import android.appwidget.AppWidgetManager;
import android.appwidget.AppWidgetProvider;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.widget.RemoteViews;

public class TestActivity extends AppWidgetProvider {
    // 自定义一个Action名
    private static final String ACTION_CLICK_NAME = "COM.LJQ.ACTION.WIDGET.CLICK";
    private RemoteViews rv;

    @Override
    public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
        System.out.println("onUpdate");
        //获取R.layout.main布局，通过类RemoteViews对布局R.layout.main里的控件进行操作
        /*rv = new RemoteViews(context.getPackageName(), R.layout.main);
        Intent intentClick = new Intent(ACTION_CLICK_NAME);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0, intentClick, 0);
        rv.setOnClickPendingIntent(R.id.tv, pendingIntent);
        
        ComponentName cmp = new ComponentName(context, TestActivity.class);
        AppWidgetManager myAppWidgetManager = AppWidgetManager.getInstance(context);
        myAppWidgetManager.updateAppWidget(cmp, rv);*/
        final int N = appWidgetIds.length;
        for (int i = 0; i < N; i++) {
            int appWidgetId = appWidgetIds[i];
            updateAppWidget(context, appWidgetManager, appWidgetId);
        }
    
    }
    
    //AppWidget生命周期: 每接收一次，广播执行一次为一个生命周期结束。
    //也就是说在重写AppWidgetProvider类里面声明全局变量做状态判断，
    //每次状态改变AppWidgetProvider再接收第二次广播时即为你重新初始化也就是说重新实例化了一次AppWidgetProvider。
    //今天我因为在里面放了一个boolean值初始化为true，观察调试看到每次进入都为TRUE故你在设置桌面组件时，
    //全局变量把它声明在另外一个实体类用来判断是没问题的，切忌放在本类。
    @Override
    public void onReceive(Context context, Intent intent) {
        System.out.println("onReceive");
        if (rv == null) {
            rv = new RemoteViews(context.getPackageName(), R.layout.main);
        }
        if (intent.getAction().equals(ACTION_CLICK_NAME)) {
            if (UtilTool.isChange) {
                rv.setTextViewText(R.id.tv, "abc");
            } else {
                rv.setTextViewText(R.id.tv, "123");
            }
            UtilTool.isChange = !UtilTool.isChange;
            AppWidgetManager appWidgetManger = AppWidgetManager.getInstance(context);
            int[] appIds = appWidgetManger.getAppWidgetIds(new ComponentName(context, TestActivity.class));
            appWidgetManger.updateAppWidget(appIds, rv);
        }else{
            super.onReceive(context, intent);
        }
        
    }
    
    private void updateAppWidget(Context context,
            AppWidgetManager appWidgeManger, int appWidgetId) {
        rv = new RemoteViews(context.getPackageName(), R.layout.main);
        Intent intentClick = new Intent();
        intentClick.setAction(ACTION_CLICK_NAME);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0, intentClick, 0);
        rv.setOnClickPendingIntent(R.id.tv, pendingIntent);
        appWidgeManger.updateAppWidget(appWidgetId, rv);
    }

}