Communications with Fragments

Because the fragment manager knows about all fragments attached to the current activity, the activity or any fragment in that activity can ask for any other fragment using the getter methods described earlier. Once the fragment reference has been obtained, the activity or fragment could cast the reference appropriately and then call methods directly on that activity or fragment. This would cause your fragments to have more knowledge about the other fragments than might normally be desired, but don’t forget that you’re running this application on a mobile device, so cutting corners can sometimes be justified. A code snippet is provided in Listing 8–12 to show how one fragment might communicate directly with another fragment.