创建Widget

以下实例是进程管理的widger，在桌面就可看到进程的数目和可用内存

1、在receive中创建ProcessWidget

public class ProcessWidget extends AppWidgetProvider {
Intent intent;

@Override
public void onDeleted(Context context, int[] appWidgetIds) {
super.onDeleted(context, appWidgetIds);
intent = new Intent(context, UpdateWidgetService.class);
context.stopService(intent);

}

@Override
public void onEnabled(Context context) {
super.onEnabled(context);
intent = new Intent(context, UpdateWidgetService.class);
context.startService(intent);
}

}

2、在清单文件当中声明

<receiver android:name="cn.dan.receiver.ProcessWidget" >
<intent-filter>
<action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
</intent-filter>

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

3、创建xml/example_appwidget_info

<?xml version="1.0" encoding="utf-8"?>
<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"
android:minWidth="294dp"
android:minHeight="72dp"
android:updatePeriodMillis="1800000"
android:initialLayout="@layout/process_widget"
>
</appwidget-provider>

3、创建widget布局process_widget

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:src="@drawable/widget_bg_portrait"
android:gravity="center_vertical" >

<LinearLayout
android:layout_width=
4000
"0.0dip"
android:layout_height="fill_parent"
android:layout_marginLeft="5.0dip"
android:layout_weight="1.0"
android:background="@drawable/widget_bg_portrait_child"
android:gravity="center_vertical"
android:orientation="vertical"
android:paddingBottom="3.0dip"
android:paddingTop="3.0dip" >

<TextView
android:id="@+id/process_count"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="10.0dip"
/>

<ImageView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="1.0dip"
android:layout_marginTop="1.0dip"
android:background="@drawable/widget_bg_portrait_child_divider" />

<TextView
android:id="@+id/process_memory"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="10.0dip"
/>
</LinearLayout>

<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center_horizontal"
android:orientation="vertical" >

<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center_vertical" >

<ImageView
android:layout_width="20.0dip"
android:layout_height="20.0dip"
android:background="@drawable/icon5" />

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/app_name"
/>
</LinearLayout>

<Button
android:id="@+id/btn_clear"
android:layout_width="90.0dip"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginTop="5.0dip"
android:background="@drawable/button_background_selected"
android:text="一键清理"
/>
</LinearLayout>

</LinearLayout>

4、创建服务更新widget界面

public class UpdateWidgetService extends Service {
private Timer timer;
private TimerTask task;// Timer 和TimerTask是做定期事件所需要的两个工具
private AppWidgetManager widgetmanager;

@Override
public IBinder onBind(Intent arg0) {
// TODO Auto-generated method stub
return null;
}

@Override
public void onCreate() {
timer = new Timer();
widgetmanager = AppWidgetManager.getInstance(getApplicationContext());
task = new TimerTask() {

@Override
public void run() {
// 更新widget的界面
ComponentName name = new ComponentName("cn.dan",
"cn.dan.receiver.ProcessWidget");// 得到这个组件
RemoteViews views = new RemoteViews("cn.dan",
R.layout.process_widget);
views.setTextViewText(
R.id.process_count,
"进程的数目:"
+ TaskUtil
.getProcessCount(getApplicationContext()));
views.setTextViewText(
R.id.process_memory,
"可用内存:"
+ TaskUtil
.getMemorySize(getApplicationContext()));
views.setTextColor(R.id.process_memory, Color.RED);
views.setTextColor(R.id.process_count, Color.RED);
Intent intent = new Intent(getApplicationContext(),
LockScreenReceiver.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(
getApplicationContext(), 0, intent, 0);
views.setOnClickPendingIntent(R.id.btn_clear, pendingIntent);
widgetmanager.updateAppWidget(name, views);

}

};
timer.schedule(task, 1000, 2000);
super.onCreate();

}

@Override
public void onDestroy() {
timer.cancel();
timer=null;
task=null;

super.onDestroy();
}

}