How to update App Widget with list view from an Activity

Question

I know this has been asked for many times but I went through the documentation from top to bottom, read all answers here and none of them helped. To be honest, each answer says something different about how to aproach this.

Now back to my question. I want to update the widget list view from some activity and I created WidgetProvider#sendUpdateBroadcastToAllWidgets() for this purpose which I call from the activity.

It eventually calls the onUpdate() so the broadcast is received correctly. But the views are not refreshed.

I also tried to call AppWidgetManager#notifyAppWidgetViewDataChanged() and refreshed the data in WidgetFactory#onDataSetChanged() but the method has never been called.

So I guess this all does not work because the remote views factory is cached but I don't know how to reliably overcome this. Any thoughts?

And what about contexts? I always have to supply one but I don't really care much which one. Does it matter?

Thanks

PROVIDER

public class WidgetProvider extends AppWidgetProvider {

    public static void sendUpdateBroadcastToAllWidgets(Context context) {
        int allWidgetIds[] = AppWidgetManager.getInstance(context).getAppWidgetIds(new ComponentName(context, WidgetProvider.class));
        Intent intent = new Intent(context, WidgetProvider.class);
        intent.setAction(AppWidgetManager.ACTION_APPWIDGET_UPDATE);
        intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_IDS, allWidgetIds);
        context.sendBroadcast(intent);
    }

    @Override
    public void onUpdate(Context context, AppWidgetManager widgetManager, int[] widgetIds) {
        for (int id : widgetIds) {
            updateWidget(context, widgetManager, id);
        }
        super.onUpdate(context, widgetManager, widgetIds);
    }

    @Override
    public void onDeleted(Context context, int[] widgetIds) {
        WidgetPreferences prefs = new WidgetPreferences(context);
        for (int widgetId : widgetIds) {
            prefs.getWidgetPreferences(widgetId).edit().clear().commit();
        }
        super.onDeleted(context, widgetIds);
    }

    private static void updateWidget(Context context, AppWidgetManager widgetManager, int widgetId) {
        RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.widget);

        // set list adapter
        Intent serviceIntent = new Intent(context, WidgetService.class);
        serviceIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, widgetId);
        serviceIntent.setData(Uri.parse(serviceIntent.toUri(Intent.URI_INTENT_SCHEME)));
        views.setRemoteAdapter(android.R.id.list, serviceIntent);
        views.setEmptyView(android.R.id.list, android.R.id.empty);

        // set widget title
        WidgetDataCategory category = new WidgetPreferences(context).getSavedCategory(widgetId);
        views.setTextViewText(R.id.titleText, context.getString(category.titleResourceId()));

        // set onclick listener - we create a pending intent template and when an items is clicked
        // the intent is filled with missing data and sent
        Intent startActivityIntent = new Intent(context, SimplePersonDetailActivity.class);
        startActivityIntent.setData(Uri.parse(startActivityIntent.toUri(Intent.URI_INTENT_SCHEME)));
        startActivityIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_SINGLE_TOP);
        startActivityIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, widgetId);
        PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, startActivityIntent, PendingIntent.FLAG_UPDATE_CURRENT);
        views.setPendingIntentTemplate(android.R.id.list, pendingIntent);

        // all hail to Google
        widgetManager.updateAppWidget(widgetId, views);
    }
}

FACTORY

public class WidgetFactory implements RemoteViewsService.RemoteViewsFactory {

    private Context context;
    private List<Person> people = new ArrayList<>();

    public WidgetFactory(Context context, Intent intent) {
        this.context = context;

        int widgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID);
        if (widgetId != AppWidgetManager.INVALID_APPWIDGET_ID) {
            WidgetPreferences prefs = new WidgetPreferences(context);

            WidgetDataCategory category = prefs.getSavedCategory(widgetId);
            int numberOfItemsToShow = prefs.getSavedLimit(widgetId);

            people = category.filterAndSlice(new PersonDao(context).getAllForGroup(Constants.SIMPLE_GROUP_ID), numberOfItemsToShow);
        }
    }

    @Override
    public void onCreate() {}

    @Override
    public void onDataSetChanged() {}

    @Override
    public void onDestroy() {}

    @Override
    public int getCount() {
        return people.size();
    }

    @Override
    public RemoteViews getViewAt(int position) {
        Person person = people.get(position);
        BigDecimal amount = ListViewUtil.sumTransactions(new TransactionDao(context).getAllForPerson(person));

        RemoteViews remoteViews = new RemoteViews(context.getPackageName(), R.layout.item_widget);
        remoteViews.setTextViewText(R.id.nameText, person.getName());
        remoteViews.setTextViewText(R.id.amountText, MoneyFormatter.withoutPlusPrefix().format(amount));

        // fill details for the onclick listener (updating the pending intent template
        // set in the WidgetProvider)
        Intent listenerIntent = new Intent();
        listenerIntent.putExtra(Constants.PERSON_ID, people.get(position).getId());
        remoteViews.setOnClickFillInIntent(R.id.widgetItem, listenerIntent);

        return remoteViews;
    }

    @Override
    public RemoteViews getLoadingView() {
        return null;
    }

    @Override
    public int getViewTypeCount() {
        return 1;
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

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

Answer 1

I would say that notifyAppWidgetViewDataChanged method should work for you.

You have to build AppWidgetManager and get appWidgetIds and then just call notifyAppWidgetViewDataChanged on your AppWidgetManager.

Pseudo Code,

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

For more, you can checkout my answer here which contains demo on github.