Android - Widget with Scrollable Listview Manual Refresh

Question

I googled and found the code to manipulate listview data using RemoteViewsService and RemoteViewsService.RemoteViewsFactory. as below

Intent svcIntent = new Intent(context, WidgetService.class);
svcIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID,appWidgetIds[i]);
svcIntent.setData(Uri.parse(svcIntent.toUri(Intent.URI_INTENT_SCHEME)));
RemoteViews widget = new RemoteViews(context.getPackageName(),R.layout.widget_layout);
widget.setRemoteAdapter(appWidgetIds[i], R.id.lstAppointments,svcIntent);

WidgetService.java contains

public class WidgetService extends RemoteViewsService {

    @Override
    public RemoteViewsFactory onGetViewFactory(Intent intent) {
        return (new WidgetViewsFactory(this.getApplicationContext(), intent));
    }

    public IBinder onBind(Intent intent) {
        // TODO Auto-generated method stub
        return super.onBind(intent);
    }
}

and wrote all the codes for fetching data from webservice in onCreate of WidgetViewsFactory implements RemoteViewsService.RemoteViewsFactory

For updating records manually or automatically every 5seconds, I found Update via Service methods as below mentioned

public class WordWidget extends AppWidgetProvider {

    static int value = 1;
    Handler handler = new Handler();
    MyRunnable myRunnable;

    @Override
    public void onUpdate(Context context, AppWidgetManager appWidgetManager,
            int[] appWidgetIds) {
        // To prevent any ANR timeouts, we perform the update in a service
        myRunnable = new MyRunnable(context);
        handler.postDelayed(myRunnable, 1000);
    }

    class MyRunnable implements Runnable {

        Context context;

        public MyRunnable(Context context) {
            this.context = context;
        }

        public void run() {
            context.startService(new Intent(context, UpdateService.class));
            handler.postDelayed(myRunnable, 1000);
        }
    }

    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, WordWidget.class);
            AppWidgetManager manager = AppWidgetManager.getInstance(this);
            manager.updateAppWidget(thisWidget, updateViews);
        }

        public RemoteViews buildUpdate(Context context) {
            RemoteViews updateViews;

            // Build an update that holds the updated widget contents
            updateViews = new RemoteViews(context.getPackageName(),
                    R.layout.widget_word);

            Log.e("value", String.valueOf(value));
            updateViews.setTextViewText(R.id.word_title, "Title");
            updateViews.setTextViewText(R.id.word_type, String.valueOf(value));
            updateViews.setTextViewText(R.id.definition, String.valueOf(value));

            value += 1;

            // When user clicks on widget it opens www.google.com
            Intent defineIntent = new Intent(Intent.ACTION_VIEW,
                    Uri.parse("https://www.google.co.in/"));
            PendingIntent pendingIntent = PendingIntent.getActivity(context, 0,
                    defineIntent, 0);
            updateViews.setOnClickPendingIntent(R.id.widget, pendingIntent);

            return updateViews;
        }

        @Override
        public IBinder onBind(Intent intent) {
            // We don't need to bind to this service
            return null;
        }
    }
}

How to update the listview automatically.. I know how to update textview as mentioned above.

Solution

You can update the ListView by using notifyAppWidgetViewDataChanged() method of AppWidgetManager. You will have to get the instance of AppWidgetManager, get the AppWidgetIds and the call appWidgetManager.notifyAppWidgetViewDataChanged(appWidgetIds, viewId);

Pseudo Code,

AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
int appWidgetIds[] = appWidgetManager.getAppWidgetIds(
                           new ComponentName(context, WidgetProvider.class));
appWidgetManager.notifyAppWidgetViewDataChanged(appWidgetIds, R.id.listview);

When you call notifyAppWidgetViewDataChanged() then the onDataSetChanged() method of RemoteViewsFactory will be called which is serving as a Adapter for your ListView. You can do web-service stuff and other operations in onDataSetChanged(), get the response and add it to your data-set which maybe ArrayList or any such Collection.

For further readings/reference you can check Keeping Collection Data Fresh part from the docs. Also you can check a demo example from my github.

Comments

[Javi Vazquez]

After looking at many threads in this site and none worked for me (probably because I am using a "Collection Widget"), this one worked as a charm! Thank you very much!

[Juan Mendez]

i was using sendBroadcast() which in turn was recreating each layout, and wasn't updating the listviews. Method notifyAppWidgetViewDataChanged only takes care of refreshing making it less expensive.