What is the correct way for sharing data among AppWidgetProvider and RemoteViewsService.RemoteViewsFactory

Question

Currently, my AppWidgetProvider is having a static data. It is used for information passing around AppWidgetProvider & RemoteViewsService

Answer 1

RemoteViewsFactory -> AppWidgetProvider

The communication from the RemoteViewsFactory to the AppWidgetProvider can be done using Broadcasts, e.g. like this:

Intent intent = new Intent(ACTION_PROGRESS_OFF);
intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, mAppWidgetId);
LocalBroadcastManager.getInstance(mContext).sendBroadcast(intent);

The AppWidgetProvider receives the event like so:

@Override
public void onReceive(final Context context, final Intent intent) {

    // here goes the check if the app widget id is ours

    final String action = intent.getAction();
    if (ACTION_PROGRESS_OFF.equals(action)) {
        // turn off the refresh spinner

Of course the broadcast action needs to be defined in the manifest:

<receiver
    android:name="...">
    <intent-filter>
        <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
        <action android:name="myPackage.ACTION_PROGRESS_OFF" />
    </intent-filter>
    <meta-data ... />
</receiver>

---

AppWidgetProvider -> RemoteViewsFactory

One way to communicate with the RemoteViewsFactory (and in your case probably the best one) is to send the information in the intent of the service you're passing to the RemoteViewsAdapter:

Intent intentRVService = new Intent(context, RemoteViewsService.class);
intentRVService.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);

// let's put in some extra information we want to pass to the RemoteViewsFactory
intentRVService.putExtra("HELLO", "WORLD");

// when intents are compared, the extras are ignored, so we need to
// embed the extras into the data so that the extras will not be ignored
intentRVService.setData(Uri.parse(intentRVService.toUri(Intent.URI_INTENT_SCHEME)));

rv.setRemoteAdapter(appWidgetId, R.id.my_list, intentRVService);
rv.setEmptyView(R.id.my_list, android.R.id.empty);

// create the pending intent template for individual list items
...
rv.setPendingIntentTemplate(R.id.my_list, pendingIntentTemplate);

appWidgetMgr.notifyAppWidgetViewDataChanged(appWidgetId, R.id.my_list);

The RemoteViewsService can easily retrieve the information from the intent and pass it along to the RemoteViewsService.RemoteViewsFactory.

I'm not 100% sure when and how your widget decides to sort the data but I'd assume if the user picks a column to sort then you have to go through the update cycle with notifyAppWidgetViewDataChanged and then you would pass that column along. If you need that information later on then you'd have to store the information somehow (SharedPreferences).