Can not add to Fragment Back Stack

Question

I open "Activity A". "Activity A" immediately does a FragmentTransaction like this to Open "Fragment A":

FragmentTransaction t = fm.beginTransaction();
ListFragment f = new ProfileFragment();
t.replace(R.id.main_frag, f, "act_frag");
f.setArguments(args);
t.commit();

"Fragment A" has a button on it that I would like to open a new Fragment ("Fragment B"), but keep the "Fragment A" in the backstack -- so if the user hits back, it is still around. So I do this:

FragmentTransaction t = fm.beginTransaction();
ListFragment f = new FollowFragment();
String username = tvUser.getText().toString();
Bundle args = new Bundle();
args.putString("follow", "watching");
args.putString("userprofile", username);
args.putInt("userIdprofile", userId);
f.setArguments(args);
t.replace(R.id.main_frag, f, "watching_frag");
t.addToBackStack("watching_frag");
t.commit();

I thought by adding t.addToBackStack(null); would do the trick; and I have done it before like that. But instead, when user hit's back, it simply closes "Activity A".

score 1 · Accepted Answer · edited Oct 27 '14 at 17:58

1

By default, when the back button is pressed, the activity is closed. I think for what you are trying to do, you'll have to override the method onBackPressed and add code to handle that for example:

@Override
public void onBackPressed() {

    FragmentManager fm = getSupportFragmentManager();
    if(fm.getBackStackEntryCount() > 0){
        fm.popBackStack();
        return;
    }
    super.onBackPressed();
}

This way, when back is pressed, it'll first check if there are any backstack entries and popback when back is pressed, if not, the default action is called.

edited Oct 27 '14 at 17:58

EboMike

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answered Oct 27 '14 at 17:55

Eric

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Wait.. is the fragment transaction for adding 'Fragment B' occurring within 'Fragment A' or the Activity? – Eric Oct 27 '14 at 18:03
It is recurring in Fragment B. Now that I think about it, that isn't always best practice if I recall. (`Fragments` communicating to each other). But the point of what I need still stands regardless of that. – TheLettuceMaster Oct 27 '14 at 18:05

score 0 · Answer 2 · answered Oct 27 '14 at 17:33

0

Have you tried putting some value inside t.addtoBackStack instead of just null? I can't test it right now but I think that might be your problem.

answered Oct 27 '14 at 17:33

Vextil

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Thanks, but this didn't work; I changed the code above to reflect what I did. – TheLettuceMaster Oct 27 '14 at 17:42
Well that's odd. I tested your code and it works just fine. Are you by any chance overriding onBackPressed()? – Vextil Oct 27 '14 at 17:51

Can not add to Fragment Back Stack

2 Answers2