Is there any way I can detect when a DialogFragment is dismissed, so that i can update its parent fragment?
One way to deal with this is to embed your DialogFragment within an Activity and display the activity as a Dialog, there's a tip in the following link that explains how:
http://developer.android.com/guide/topics/ui/dialogs.html
You can use this to update the underlying Fragment because when the Dialog (which is an Activity) is finished, onResume() will be called on the underlying fragment. Add code to update the state of the fragment in the onResume() method and that's all there is too it.