savedInstanceState when restoring fragment from back stack

Question

Can I use savedInstanceState() to save the state when removing a fragment, then restore the state when I pop the fragment off the back stack? When I restore the fr

Answer 1

I like to store the View I return in onCreateView as a global variable and then when I return I simply check this:

if(mBaseView != null) {
        // Remove the view from the parent
        ((ViewGroup)mBaseView.getParent()).removeView(mBaseView);
        // Return it
        return mBaseView;
    }

Answer 2

The problem is that the fragment needs to have an Id or Tag associated with it in order for the FragmentManager to keep track of it.

There are at least 3 ways to do this:

1. In xml layout declare an Id for your fragment:

   android:id=@+id/<Id>
   

2. If your fragments container View has an Id, use FragmentTransaction:

   FragmentTransaction  add (int containerViewId, Fragment fragment)
   

3. If your fragment is not associated with any View (e.g. headless fragment), give it a Tag:

   FragmentTransaction  add (Fragment fragment, String tag)
   

Also, see this SO answer.

Answer 3

onSaveInstanceState is (unfortunately) not called in normal back-stack re-creation of a fragment. Check out http://developer.android.com/guide/components/fragments.html#Creating and the answer on How can I maintain fragment state when added to the back stack?

Answer 4

FWIW, I hit this as well, but in my case onSaveInstanceState was called properly and I pushed in my state data when a new activity fragment was brought up on the smartphone. Same as you, the onActivityCreated was called w/ savedInstanceState always null. IMHO, I think it's a bug.

I worked around it by creating a static MyApplication state and putting the data there for the equivalent of "global variables"...