Question

I am developing an appwidget that uses the RemoteViews to display a ListView. For simplicity’s sake, I will give an analogy of the appwidget’s functionality:

1. The user will select to add the appwidget to the home screen. Upon selecting the widget, a configuration activity is launched and the user selects from one recipe from a list of recipes.
2. Upon selecting the recipe from the configuration activity, the configuration activity broadcasts the AppWidgetManager.ACTION_APPWIDGET_UPDATE intent. This intent received and handled in the onReceive method of my AppWidgetProvider class. From here the RemoteView is instantiated and passed into the AppWidgetManager.updateAppWidget() method. This proceeds to fill in the ListView of ingredients.

This all works as expected, except when I attempt to manually update the ListView from the appwidget. I have set a PendingIntent to re-launch the configuration activity, which also works. Unfortunately, the call to AppWidgetManager.updateAppWidget() does not get called instantly as it did when being launched upon adding it to the home screen and the ListView does not get updated. The update does get called, however, after scrolling down the list a ways (until it gets passed the number of rows it has loaded in its cache, I reckon). This fires off my FlightBoardAppWidgetService and ViewsFactory as it should. It is almost as if the updateAppWidget is getting put into some lazily-loaded queue. I tried to look at the Android source code to see how AppWidgetManager.updateAppWidget() is coded, but it appears to be hidden.

tl;dr: AppWidgetManager.updateAppWidget() does not always get called instantly, what gives?

Is there any way to get the ListView to update when it is actually called? What am I doing wrong? Thanks!

Answer 1

Well, I ended up solving the problem finally. It is somewhat of a hack, but I ended up solving the problem by declaring a refresh broadcast and an update broadcast. Each time I want to update the widget I call updateAppWidget(), and then from the function that receives and handles this broadcast, I launch another broadcast that calls notifyChanged. This works all of the time!