onBackPressed with viewpager activity and fragments

Question

i have a viewpager activity containing fragment named OneFragment.

The Onefragment contains a recyclerview,on items click a fragment called DescriptionFragment opens.

This is how i opened the DescriptionFragment from the Adapter:

 Fragment descriptionFragment = new DescriptionFragment ();
                FragmentTransaction transaction = mContext.beginTransaction();
                transaction.replace(R.id.framelayout, descriptionFragment).addToBackStack(null).commit();

Problem: When i click on backpress button the app finishes.

I want on backpress to close the DescriptionFragment and return back to the OneFragment

Sanjog Shrestha · Answer 1 · 2017-04-15T14:59:33.580

2

Look at the getFragmentManager().popBackStack() methods (there are several to choose from)

http://developer.android.com/reference/android/app/FragmentManager.html#popBackStack()

To elaborate, this is my solution (placed in an Activity):

@Override
public void onBackPressed(){
    FragmentManager fm = getFragmentManager();
    if (fm.getBackStackEntryCount() > 0) {
        Log.i("MainActivity", "popping backstack");
        fm.popBackStack();
    } else {
        Log.i("MainActivity", "nothing on backstack, calling super");
        super.onBackPressed();  
    }
}

edited Apr 15 '17 at 14:59

answered Apr 15 '17 at 14:43

Sanjog Shrestha

827
9
16

Please one more question: How to handle the on resume method? Because when i am resuming the app it restarts it doesn t resume – Mahdi H Apr 15 '17 at 15:14

Muhib Pirani · Accepted Answer · 2017-04-15T14:48:27.377

1

add fragment to stack while comitting a transaction like this

transaction.addToBackStack(OneFragment.getClass().getName);

and your transaction code should look somrething like this

FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction transaction= fragmentManager.beginTransaction();
transaction.replace(..............);
transaction.addToBackStack(null);
transaction.commit();

edited Apr 15 '17 at 14:48

answered Apr 15 '17 at 14:42

Muhib Pirani

710
1
6
15

I used(OneFragment.class.getName()) but still getting same result – Mahdi H Apr 15 '17 at 14:52
Instead of mContext.beginTransactiin() try adding fragmentManager.beginTransaction() – Muhib Pirani Apr 15 '17 at 14:57
It worked i was using getChildFragmentManager i changed to FragmentMangaer – Mahdi H Apr 15 '17 at 15:11
Please one more question: How to handle the on resume method? Because when i am resuming the app it restarts it doesn t resume – Mahdi H Apr 15 '17 at 15:14
Everytime either you open app or resume ,onResume method is called. What is exactly the issue you are facing? – Muhib Pirani Apr 15 '17 at 15:24
When i pause the app and then resume it..the app relaunches from 0..i want the app resume my OneFragment – Mahdi H Apr 15 '17 at 15:26
i think it is realted to savedInsatance state of fragment and activity, this might help http://stackoverflow.com/questions/6337217/how-to-return-to-the-latest-launched-activity-when-re-launching-application-afte – Muhib Pirani Apr 15 '17 at 15:31
Thanks it worked on HomeButton press not the backbutton any idea? – Mahdi H Apr 15 '17 at 15:57
1

when you press back button the onDestroy method is called and now when you come back there wont be any savedInsatanceState from which the activity can be resumed. – Muhib Pirani Apr 15 '17 at 15:59
Big Thank for help! – Mahdi H Apr 15 '17 at 16:14

onBackPressed with viewpager activity and fragments

2 Answers2