How to save fragment state while navigating through activity

Question

May be the title of the question is not clear . Or I have failed to describe what I am looking for .

I have two activity in my app . Lets say their name is "ActivityA" and "ActivityB" . Under "ActivityA" there are few fragments . Lets say their name is "FragmentA" "FragmentB" "FragmentC" "FragmentD" etc . The default fragment is "FragmentA" , that means when the activity starts "FragmentA" starts .

Now , if I navigate to "ActivityB" , and came back to "ActivityA" , it always open "FragmentA" . But what I want is if I navigate to "FragmentB" , and then navigate to "ActivityB" , and back to "ActivityA" it starts "FragmentA" , but I want "FragmentB" to start ,in which I was beforer

to navigate from Activity B to Activity A, do you start activity A using intent or use back button? — Fabin Paul, Apr 20 '16 at 11:09
at what activity lifecycle are you adding the default fragments? or is the fragments added via xml? — Fabin Paul, Apr 20 '16 at 11:38

score 1 · Answer 1 · answered Apr 20 '16 at 11:23

Not sure if I understand you correctly, but I think what you need to do is startActivityForResult when you call your ActivityB. When you press BackButton you provide your necessary information about the fragment to be called and catch these infos in ActivityB's onActivityResult then navigate to the desired Fragment.

score 1 · Accepted Answer · edited May 23 '17 at 12:22

You might be restarting ActivityA from ActivityB via startActivity() instead of finishing ActivityB. If it is so, just finish your ActivityB. Then you will be on the last shown fragment in your ActivityA.

Or you can also use onSaveInstanceState method to keep trace of your Fragments. This answer can help you with this.

Or using following with your ActivityA can also solves your issue:

<activity android:name=".ActivityA" android:launchMode="singleTop">

score 1 · Answer 3 · answered Apr 20 '16 at 11:36

Create a method that returns the last visible fragment

 public Fragment getVisibleFragment(){
        FragmentManager fragmentManager = MainActivity.this.getSupportFragmentManager();
        List<Fragment> fragments = fragmentManager.getFragments();
        if(fragments != null){
            for(Fragment fragment : fragments){
                if(fragment != null && fragment.isVisible())
                    return fragment;
            }
        }
        return null;
    }

Create an instance of Fragment class and set it to null

Fragment lastVisibleFragment = null;

in onPause save the last fragment

  @Override
    protected void onPause() {
        super.onPause();
         lastVisibleFragment = getVisibleFragment();
    }

Then in onResume() add the last fragment you were in if not null

   @Override
    protected void onResume() {
        super.onResume();
        if(lastVisibleFragment !=null){    
            getSupportFragmentManager().beginTransaction()
                    .add(yourFrameLayout, lastVisibleFragment)
                    .commit();
        }
       else{ //Add first fragment you were adding}
    }

I have tried your method . I have a navigation drawer in my app . getVisibleFragment() returns my Navigation DrawerFragment — Mithun Sarker Shuvro, Apr 20 '16 at 12:21

How to save fragment state while navigating through activity

3 Answers3