Android appwidget 服务无法启动

Question

当我在 Debug模式下运行时，我似乎无法到达服务内部的任何断点，这是为什么？

    @Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager,
        int[] appWidgetIds) {
    context.startService(new Intent(context, UpdateService.class));
}

public static class UpdateService extends Service {

    @Override
    public void onStart(Intent intent, int startId) {
        // Build the widget update for today
        RemoteViews updateViews = buildUpdate(this);

        // Push update for this widget to the home screen
        ComponentName thisWidget = new ComponentName(this, WidgetProvider.class);
        AppWidgetManager manager = AppWidgetManager.getInstance(this);
        manager.updateAppWidget(thisWidget, updateViews);
    }

    public RemoteViews buildUpdate(Context context) {
        return new RemoteViews(context.getPackageName(), R.id.widget_main_layout);
    }


    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }
}

Answer 1

“onUpdate”方法仅在小部件初始化(例如放在主屏幕上)或 updatePeriodMillis 过期时执行。如果你想执行服务，例如通过单击小部件，您必须像这样“附加”一个待处理的 Intent :

@Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
final Intent intent = new Intent(context, UpdateService.class);
PendingIntent pendingIntent = PendingIntent.getService(context, 0, intent, 0);

// Get the layout for the App Widget and attach an on-click listener to
// the button
RemoteViews views = new RemoteViews(context.getPackageName(), R.layout....);
views.setOnClickPendingIntent(R.id.button, pendingIntent);
for(int i=0,n=appWidgetIds.length;i<n;i++){
    int appWidgetId = appWidgetIds[i];
    appWidgetManager.updateAppWidget(appWidgetId , views);
}

(已清理的工作小部件版本)。

重点是，onUpdate() 方法实际上很少执行。与小部件的真正交互是通过未决 Intent 指定的。