Android SyncAdapter stuck in infinite sync loop

问题:

I'm writing an Android Sync Adapter and basically having a problem with it syncing in an infinite loop. As soon as the sync completes it starts all over again.

Thank you,

Regards,

Akshay

@Override
    public void onPerformSync(final Account account, final Bundle extras, final String authority, final ContentProviderClient provider, final SyncResult syncResult) {
        Log.i("Sync result full sync = " + syncResult.fullSyncRequested);
        Log.i("Sync result " + syncResult.toDebugString());
        Log.i("Bundle " + extras.toString());

        final CountDownLatch latch = new CountDownLatch(3);


        final CachedDataReceiver globalStreamRefreshReciever = new CachedDataReceiver(null) {
            @Override
            protected void onComplete(int resultCode) {latch.countDown();}
            @Override
            protected void onError() {latch.countDown();}
        };

        final CachedDataReceiver newMessagesReciever = new CachedDataReceiver(null) {
            @Override
            protected void onComplete(int resultCode) {latch.countDown();}
            @Override
            protected void onError() {latch.countDown();}
        };

        final CachedDataReceiver getViewedMessagesReciever = new CachedDataReceiver(null) {
            @Override
            protected void onComplete(int resultCode) {latch.countDown();showAnyNewInboxItemAlerts(getApplicationContext());}
            @Override
            protected void onError() {latch.countDown();}
        };


        /*long currentTime = System.currentTimeMillis();
        long netTime = currentTime-getLastSyncTimeStamp();
        boolean shouldSync = (netTime - getSyncInterval()) >=0;
        if (!shouldSync && getSyncInterval()!=Constants.INVALID_ITEM){
            Log.i("Current time = " + currentTime + " last sync = " + getLastSyncTimeStamp() + " sync interval = " + getSyncInterval());
            Log.i("Difference = " + (netTime - getSyncInterval()));
            return;
        }*/



        if (user.isUserLoggedIn() && (!TextUtils.isEmpty(user.peekLoggedInUserAccountToken(null)))){ 
            startService(api.getGlobalStream(0,10,globalStreamRefreshReciever));
            startService(api.getNewMessagesInbox(newMessagesReciever));
            startService(api.getViewedMessagesInbox(false, getViewedMessagesReciever));
            addTimeStamp(); 
            Log.i("in sync");
            try {
                latch.await(1, TimeUnit.MINUTES);
            } catch (InterruptedException interruptedException) {
                interruptedException.printStackTrace();
                Log.e("Error in latch while sync ");
            }

        }
    }

回答1:

You're missing a lot of code there, hard to find your problem when you don't tell us what you're doing.

Going out on a limb with a guess at your problems...

Do either addTimeStamp() or the various services you create modify the data stored in your ContentProvider?

If so, does your ContentProvider call ContentResolver.notifyChange(uri, null)?

If so, your ContentProvider notifies Android that it has changed and needs a sync, thus driving a loop.

The API is notifyChange (Uri uri, ContentObserver observer, boolean syncToNetwork). you need to call with notifyChange(uri, null, false); -- This indicates that you've pulled a change from the network and that it should not be pushed back to the network, thus breaking the loop.

回答2:

when we have ContentObserver registered, the sync adapter will go in loop even after setting syncToNetwork as false.

notifyChange(uri, null, false);