I have a problem that difficult to understand in quiz of chapter 12- Dialog that: first Activity host a list fragnment, this list fragment launch Crime_Pager_Activity, which hosts Crime_Fragment. The date button in Ctrime_Fragment launch user_option_fragment, which have 2 button for user to choose time picker or date picker. When user click 1 button (for ex: date picker) , it launchs DatePickerFragment. There is one “ok” button for completing setting up in DatePickerFragment. But my question is when clicking “ok”, why it goes back to Crime_Fragment but no use_option_frament ? Because i think user_option_fragment is parent of it, and i want it go back to user_option_fragment. I dont have any solution. Please help me.