Question

Hi I have an app that plays large files. I would like to extend with downloadable add-ons. I would for example have certain sounds seperate installable package.

Answer 1

You can test for the existence of your add-ons using Intents. Create an explicit Intent and check the PackageManager to see if it exists. If it does, unlock the behavior.

public boolean isIntentAvailable(Context context, String action) {
  final PackageManager packageManager = context.getPackageManager();
  final Intent intent = new Intent(action);
  List<ResolveInfo> resolveInfo = packageManager.queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY);
  return resolveInfo.size() > 0;
}

If you want to do something more complicated then your add-ons need to have Activities that are triggered with Intents, Services that you call via AIDL, or some other mechanism to add the functionality.