Android RemoteViews ListView Scroll

Question

Im trying to scroll a ListView to a particular position in an AppWidget.

However it does not do anything, i also tried the setPosit

Answer 1

Issue: ListView does not have any children until it is displayed. Hence calling setScrollPosition right after setting adpater has no effect. Following is the code in AbsListView which does this check:

final int childCount = getChildCount();
if (childCount == 0) {
    // Can't scroll without children.
    return;
}

Solution: Ideally I would have used ViewTreeObserver.OnGlobalLayoutListener for setting the ListView scroll position, but it is not possible in case of remote views. Set the scroll position and invoke partiallyUpdateAppWidget in a runnable with some delay. I've modified the Android weather widget code and shared in git hub.

public class MyWidgetProvider extends AppWidgetProvider {

    private static HandlerThread sWorkerThread;
    private static Handler sWorkerQueue;

    public MyWidgetProvider() {
        // Start the worker thread
        sWorkerThread = new HandlerThread("MyWidgetProvider-worker");
        sWorkerThread.start();
        sWorkerQueue = new Handler(sWorkerThread.getLooper());
    }

    public void onUpdate(Context context, final AppWidgetManager appWidgetManager, int[] appWidgetIds) {
        for (int i = 0; i < appWidgetIds.length; ++i) {
            ...
            final RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.widget_layout);
            views.setRemoteAdapter(R.id.lvWidget, svcIntent);

            sWorkerQueue.postDelayed(new Runnable() {

                @Override
                public void run() {
                    // TODO Auto-generated method stub
                    views.setScrollPosition(R.id.list, 3);
                    appWidgetManager.partiallyUpdateAppWidget(appWidgetIds[i], views);
                }

            }, 1000);

            appWidgetManager.updateAppWidget(appWidgetIds[i], views);
            ...
        }
    }
}

Here is the screen record. It scrolls to 5th position.