Android Fragment View State Loss When Using FragmentTransaction.replace()

android, android-fragmentactivity, android-fragments, android-lifecycle

Solution

Without being able to see the code of your fragments this is a bit of a guess, but in the past I've run into this same issue and I've found that resetting the adapter in your `ListFragment` in `onViewStateRestored` seems to do the trick.

public void onViewStateRestored (Bundle savedInstanceState)
{
    super.onViewStateRestored (savedInstanceState);
    setListAdapter(new ArrayAdapter(Activity, R.layout.nav_item, objects));
}

Which is weird considering the documentation states that this method is called after `onActivityCreated` but before `onStart`. But it seems that it is also called at other times because when the most recent fragment transaction is popped off the back stack this method is called before the previously replaced fragment is displayed. The activity that owns the fragments has not been paused or obscured in any way, so according to the docs `onViewStateRestored` should not be called since just the fragments were modified. But this seems to work anyway.

Problem

I am having a pretty big issue and I am not quite understanding what is happening. I am developing an application that uses Fragments (from the support library) and am using `FragmentTransaction.replace()` to place new Fragments on to the back stack and replace the old one. The code looks as follows: ``` FragmentManager fm = getSupportFragmentManager(); FragmentTransaction ft = ft.beginTransaction(); // Animations in my res/anim folder ft.setCustomAnimations(R.anim.slide_in_right, R.anim.slide_out_left, R.anim.slide_in_left, R.anim.slide_out_right); ft.replace(R.id.fragment_container, newFragment, tag); ft.addToBackStack(null); ft.commit(); ``` This is successful in replacing my fragment. My issue is the following. In one Fragment, I have a list of items that is built from user input. Now, when the user clicks next and then clicks the back button (to return to the list), the list is empty because the view is destroyed. Now, I have noted the following: - onSaveInstanceState is not called. I believe this is because that is only called when the parent Activity tells it to. Based on the docs: " There are many situations where a fragment may be mostly torn down (such as when placed on the back stack with no UI showing), but its state will not be saved until its owning activity actually needs to save its state.". Apparently, performing a replace on the FragmentTransaction is not one of those times. Does anyone have confirmation on this or a better explanation? - setOnRetainInstanceState(true) is not helpful in this situation. Again, I believe this has to do with info from the docs: "Control whether a fragment instance is retained across Activity re-creation (such as from a configuration change)". I am not performing any action in re-creating the activity so this is of no use. So, I guess my main question is: is there a way to preserve the View state (simply retain the Fragment) when using `replace`? There is `FragmentTransaction.add()`, but there are a few issues with this as well. One being that the exit animation is not performed, thus the animation is not correct. Another is that the new Fragment that the old fragment (the one that is being put into a non-visible state) is still clickable. For example, if I have a ListFragment, and I place a content fragment on top of that by using add, I can still click the list items in the ListFragment.

Original source