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 {

@Override
public void onDeleted(Context context, int[] appWidgetIds) {
}

@Override
public void onDisabled(Context context) {
// TODO Auto-generated method stub
super.onDisabled(context);
}

@Override
public void onEnabled(Context context) {
// TODO Auto-generated method stub
super.onEnabled(context);
}

@Override
public 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;
}

@Override
public 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();

@Override
public 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;
}
}

@Override
public void onCreate() {
super.onCreate();
}

@Override
public 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();
}
}
}

@Override
public 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();
}
}