DialogFragment with setRetainInstanceState(true) is not displayed after the device is rotated

Question

I have a question regarding DialogFragment. I am trying to make a dialog that keeps it's state after the device is rotated. This dialog has a bunch of references to things such as adapters and other heavier objects and I need this to be kept upon rotation, if possible without having to make every reference Parcelable or Serializable in order for me to use onSaveInstanceState to save and restore them when the original activity is re-created.

I've noticed there's a method called setRetainInstance(boolean) on the DialogFragment which allows you to keep the dialog fragment instance when the activity is re-created. However, when I rotate the device now, the dialog is not showing anymore. I know I can get it from the activity's FragmentManager, but I cannot find a way to make it visible again. Any suggestions on this?

Thanks, Mihai

Answer 1

There are few things you need to do :

1. use instance factory method to initiate a DialogFragment instance like this :

   public static MyDialogFragment newInstance(MyModel model) {
       MyDialogFragment myDialogFragment = new MyDialogFragment();
       Bundle bundle = new Bundle();
       bundle.putSerializable("MODEL", model);
       myDialogFragment .setArguments(bundle);
       return myDialogFragment;
   }
   

2. by putting setRetainInstance(true) in onCreate, all of your references declared in the fragment will be kept after the original activity is re-created

   @Override
   public void onCreate(Bundle icicle) {
       this.setCancelable(true);
       setRetainInstance(true);
       super.onCreate(icicle);
   
   }
   

3. avoiding disappear on rotation by doing this

   @Override
   public void onDestroyView() {
       if (getDialog() != null && getRetainInstance())
           getDialog().setDismissMessage(null);
       super.onDestroyView();
   

   }

4. get your object by using

   (MyModel) getArguments().getSerializable("MODEL")