Android实现widget定时更新

在开发Android的widget时，第一个需要解决的问题就是怎么实现让widget定时更新，在查阅比较多的资料后，一般情况用Service在后台更新，废话不多说，贴代码如下：

Widget:

public class NewsWidgetProvider extends AppWidgetProvider {@Overridepublic void onDeleted(Context context, int[] appWidgetIds) {}@Overridepublic void onDisabled(Context context) {// TODO Auto-generated method stubsuper.onDisabled(context);}@Overridepublic void onEnabled(Context context) {// TODO Auto-generated method stubsuper.onEnabled(context);}@Overridepublic void onUpdate(Context context, AppWidgetManager appWidgetManager,int[] appWidgetIds) {NewsService.updateAppWidgetIds(appWidgetIds);context.startService(new Intent(context,NewsService.class));}public static RemoteViews updateAppWidget(Context context,List<RssNews> list) {RemoteViews views = new RemoteViews(context.getPackageName(),R.layout.appwidget_layout);if (list.size() > 3) {views.setTextViewText(R.id.textView01, list.get(0).title);views.setTextViewText(R.id.textView02, list.get(1).title);views.setTextViewText(R.id.textView03, list.get(2).title);}Intent detailIntent=new Intent(context,NewsSiteList.class);PendingIntent pending=PendingIntent.getActivity(context, 0, detailIntent, 0);views.setOnClickPendingIntent(R.id.textView01, pending);views.setOnClickPendingIntent(R.id.textView02, pending);views.setOnClickPendingIntent(R.id.textView03, pending);return views;}@Overridepublic void onReceive(Context context, Intent intent) {super.onReceive(context, intent);}}

Service:

public class NewsService extends Service implements Runnable {private static final String TAG="NewsService"; private static Queue<Integer> sAppWidgetIds=new LinkedList<Integer>();public static final String ACTION_UPDATE_ALL = "com.xxxx.news.UPDATE_ALL";private static boolean sThreadRunning = false;private static Object sLock = new Object();@Overridepublic IBinder onBind(Intent intent) {return null;}public static void updateAppWidgetIds(int[] appWidgetIds){synchronized (sLock) {for (int appWidgetId : appWidgetIds) {sAppWidgetIds.add(appWidgetId);}}}public static int getNextWidgetId(){synchronized (sLock) {if (sAppWidgetIds.peek() == null) {return AppWidgetManager.INVALID_APPWIDGET_ID;} else {return sAppWidgetIds.poll();}}}private static boolean hasMoreUpdates() {synchronized (sLock) {boolean hasMore = !sAppWidgetIds.isEmpty();if (!hasMore) {sThreadRunning = false;}return hasMore;}}@Overridepublic void onCreate() {super.onCreate();}@Overridepublic void onStart(Intent intent, int startId) {super.onStart(intent, startId);if (null != intent) {if (ACTION_UPDATE_ALL.equals(intent.getAction())) {AppWidgetManager widget = AppWidgetManager.getInstance(this);updateAppWidgetIds(widget.getAppWidgetIds(new ComponentName(this, NewsWidgetProvider.class)));}}synchronized (sLock) {if (!sThreadRunning) {sThreadRunning=true;new Thread(this).start();}}}@Overridepublic void run() {SharedPreferences setting=getSharedPreferences("com.xxxx.news_preferences", 0);String updateTime=setting.getString("list_time", "1800000");String updateUrl=setting.getString("list_site", "xxxxxxxxx");AppWidgetManager appWidgetManager=AppWidgetManager.getInstance(this);RemoteViews updateViews=null;while (hasMoreUpdates()) {int appWidgetId=getNextWidgetId();List<RssNews> listNews = NewsContenttList.getNewsList(updateUrl);if (listNews != null) {updateViews = NewsWidgetProvider.updateAppWidget(this, listNews);}if (updateViews != null) {appWidgetManager.updateAppWidget(appWidgetId, updateViews);}}Intent updateIntent=new Intent(ACTION_UPDATE_ALL);updateIntent.setClass(this, NewsService.class);PendingIntent pending=PendingIntent.getService(this, 0, updateIntent, 0);Time time = new Time();long nowMillis = System.currentTimeMillis();time.set(nowMillis+Long.parseLong(updateTime));long updateTimes = time.toMillis(true);Log.d(TAG, "request next update at "+updateTimes);AlarmManager alarm=(AlarmManager)getSystemService(Context.ALARM_SERVICE);alarm.set(AlarmManager.RTC_WAKEUP, updateTimes, pending);stopSelf();}}本文转载自：http://www.oschina.net/question/5189_8939

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