在onSaveInstanceState（）之后调用的onResumeFragments（）

Question

My activity may show a DialogFragment when it resumes. As suggested in this fragment transactions tutorial , I'm doing that in onResumeFragments() to avoid the dreaded IllegalStateException: Can not perform this action after onSaveInstanceState . For the most part, all is well.

But my activity also has an OnSharedPreferenceChangeListener that restarts the activity when a certain preference is changed. The preference change that triggers the listener is caused by making a selection in a Spinner . If the activity restarts itself by calling recreate() , I get the IllegalStateException . But if the activity restarts itself like this, there's no problem:

finish();
final Intent intent = new Intent(StartActivity.this, StartActivity.class);
startActivity(intent);

I'd prefer to use recreate() because I want my instance state to be saved. Why would this result in onResumeFragments() being called after onSaveInstanceState() ?

Answer 1

Well, I feel kind of dumb. I had a fragment that called setRetainInstance(true) but cached a reference to its activity in onCreate(...) instead of onActivityCreated(...) . The fragment was attempting to display a dialog using the old activity. (To be more precise, the activity was indirectly calling a method on the fragment from onResumeFragments() .) Pretty messy. I should probably rethink the whole relationship between the fragment and the activity.

Edit: I've since discovered another way this can happen that isn't my fault. If the lock screen is shown over a running activity, onSaveInstanceState() is called. But when the lock screen is dismissed, onRestoreInstanceState() is not called between onResume() and onResumeFragments() . This bug is at least five years old. Thanks, Google.