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);
}

}