AppWidget 框架类

1.AppWidgetProvider

继承自 BroadcastRecevier ，在AppWidget 应用 update、enable、disable 和 delete 时接收通知。其中，onUpdate、onReceive 是最常用到的方法，它们接收更新通知。
继承自 AppWidgetProvider 可实现的方法为如下：
onDeleted(Context context, int[] appWidgetIds)
onDisabled(Context context)
onEnabled(Context context)
onReceive(Context context, Intent intent)
onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds)

2.AppWidgetProvderInfo

描述 AppWidget 的大小、更新频率和初始界面等信息，以XML 文件形式存在于应用的 res/xml/目录下。

3.AppWidgetManger

负责管理 AppWidget ，向 AppwidgetProvider 发送通知。
bindAppWidgetId(int appWidgetId, ComponentName provider)：通过给定的ComponentName 绑定appWidgetId
getAppWidgetIds(ComponentName provider)：通过给定的ComponentName 获取AppWidgetId
getAppWidgetInfo(int appWidgetId)：通过AppWidgetId 获取 AppWidget 信息
getInstalledProviders()：返回一个List<AppWidgetProviderInfo>的信息
getInstance(Context context)：获取 AppWidgetManger 实例使用的上下文对象
updateAppWidget(int[] appWidgetIds, RemoteViews views)：通过appWidgetId 对传进来的 RemoteView 进行修改，并重新刷新AppWidget 组件
updateAppWidget(ComponentName provider, RemoteViews views)：通过 ComponentName 对传进来的 RemoeteView 进行修改，并重新刷新AppWidget 组件
updateAppWidget(int appWidgetId, RemoteViews views)：通过appWidgetId 对传进来的 RemoteView 进行修改，并重新刷新AppWidget 组件

4.RemoteViews

一个可以在其他应用进程中运行的类，向 AppWidgetProvider 发送通知。

Demo

一个简单的AppWidget步骤

1、在res下新建xml文件夹，然后新建appwidget_provider.xml

<?xml version="1.0" encoding="UTF-8"?>
<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"
	android:minWidth="60dp"
	android:minHeight="30dp"
	android:updatePeriodMillis="86400000"    
	android:initialLayout="@layout/widget_main">
</appwidget-provider>

2、在layout文件夹下新建布局文件widget_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/layout"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
		<TextView
        android:id="@+id/tv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:clickable="true"
        android:text="点点点我" >
		</TextView>
</LinearLayout>

3、定义类继承自AppWidgetProvider

public class MyAppWidgetProvider extends AppWidgetProvider {
    private RemoteViews remoteViews;

    @Override
    public void onReceive(Context context, Intent intent) {
        super.onReceive(context, intent);
        if (remoteViews == null) {
            remoteViews = new RemoteViews(context.getPackageName(), R.layout.widget_main);
        }
        if (intent.getAction().equals("com.example.widgettest")) {
            if (CommonValiable.isChange) {
                remoteViews.setTextViewText(R.id.tv, "点点点我");

            } else {
                remoteViews.setTextViewText(R.id.tv, "买买买我");
            }
            Toast.makeText(context, Boolean.toString(CommonValiable.isChange), Toast.LENGTH_LONG).show();
            CommonValiable.isChange = !CommonValiable.isChange;
        }
        AppWidgetManager appWidgetManger = AppWidgetManager.getInstance(context);
        int[] appIds = appWidgetManger.getAppWidgetIds(new ComponentName(context, MyAppWidgetProvider.class));
        appWidgetManger.updateAppWidget(appIds, remoteViews);


    }

    @Override
    public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
        final int N = appWidgetIds.length;
        for (int i = 0; i < N; i++) {
            int appWidgetId = appWidgetIds[i];
            updateAppWidget(context, appWidgetManager, appWidgetId);
        }
    }
    public void updateAppWidget(Context context, AppWidgetManager appWidgeManger, int appWidgetId) {
        remoteViews = new RemoteViews(context.getPackageName(), R.layout.widget_main);
        Intent intent = new Intent("com.example.widgettest");
        PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0, intent, 0);
        remoteViews.setOnClickPendingIntent(R.id.tv, pendingIntent);
        appWidgeManger.updateAppWidget(appWidgetId, remoteViews);
    }
}

4、在清单文件的application节点下声明如下

<receiver android:name=".MyAppWidgetProvider" >
    <meta-data
        android:name="android.appwidget.provider"
        android:resource="@xml/appwidget_provider" >
    </meta-data>

    <intent-filter>
        <action android:name="com.example.widgettest" />
        <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
    </intent-filter>
</receiver>

Android AppWidget开发实战