What is the best way to handle updates when the calendar syncs new events?

Question

With ICS, we now have APIs for the Calendar! :)

My question is, how do we determine if an event has been updated. Ideally this could be done with a BroadcastReceiver, but I don't think there is one that is publicly accessible. There is some event broadcasted, but I don't think it's accessible to non-system apps.

02-06 23:05:05.316: I/CalendarProvider2(9201): Sending notification intent: Intent { act=android.intent.action.PROVIDER_CHANGED dat=content://com.android.calendar }
02-06 23:05:05.320: W/ContentResolver(9201): Failed to get type for: content://com.android.calendar (Unknown URL content://com.android.calendar)

This is my work around for now. Is there a better way? Users can get squimish if they see a service running for along time and often will kill it to save battery life.

public class CalendarUpdatedService extends Service {

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {

        int returnValue = super.onStartCommand(intent, flags, startId);

        getContentResolver().registerContentObserver(
                CalendarContract.Events.CONTENT_URI, true, observer);

        return returnValue;
    }

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

    ContentObserver observer = new ContentObserver(new Handler()) {

        @Override
        public boolean deliverSelfNotifications() {
            return true;
        }

        @Override
        public void onChange(boolean selfChange) {
            super.onChange(selfChange);

            //code goes here to update
        }
    };

}

Answer 1

I use a static singleton class (you could also extend Application) with methods to register/unregister multiple observers for different providers such as the calendar provider(s). I store this in a HashMap so I can determine which observers are registered at a later time.

It is ugly but there doesn't seem to be a better solution.

EDIT This receiver:

public class CalendarChangedReceiver extends BroadcastReceiver {
    private static final String TAG = "CalendarChangedReceiver";

    @Override
    public void onReceive(Context context, Intent intent) {
        Log.d(TAG, "calendar changed! "+intent.toUri(Intent.URI_INTENT_SCHEME));
    }
}

With this manifest declaration:

<receiver android:name=".CalendarChangedReceiver">
    <intent-filter>
        <action android:name="android.intent.action.PROVIDER_CHANGED"/>
        <data android:scheme="content"/>
        <data android:host="com.android.calendar"/>
    </intent-filter>
</receiver>

Will catch changes to Events and Calendars in ICS. If you are using the old undocumented calendar provider the only solution is ContentObserver(s) in a static class or service.