What information can an Android App tell about other apps on a phone?

If I had an app that wanted to assess what other apps I had on my phone and make recommendations for new 开发者_开发问答ones, what information can I read off the phone and send back to our server?

Try PackageManager: http://developer.android.com/reference/android/content/pm/PackageManager.html

final Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);
        mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);
        final List pkgAppsList = getPackageManager().queryIntentActivities(   mainIntent, 0);