call popBackStack result more than one times of onBackPressed

Question

My app has this flow

Activity (TabLayout) -> Fragment 1 -> Fragment 2 -> Fragment 3

When I either press back on Fragment 2 or Fragment 3, I already go back to Fragment 1. I want to go back to Fragment 2 if I am on Fragment 3.

From fragment 1 to fragment 2

Frag2 childFrag = new Frag2();
getChildFragmentManager().beginTransaction().add(R.id.frag2_frame, childFrag)
    .addToBackStack(null)
    .commit();

From fragment 2 to fragment 3

Frag3 childFrag = new Frag3();
getChildFragmentManager().beginTransaction().add(R.id.frag3_frame, childFrag)
    .addToBackStack(null)
    .commit();

onBackPressed in Activity

// a fragments list for tablayout
ArrayList<Fragment> fragments = new ArrayList<>();    

public void onBackPressed(){
    fragments.get(selectedTab).getChildFragmentManager().popBackStack();
}

score 0 · Answer 1 · answered Apr 25 '18 at 13:04

0

Try adding backStack

Frag2 childFrag = new Frag2();
getFragmentManager().beginTransaction().add(R.id.frag2_frame, childFrag)
    .addToBackStack("Frag2 ")
    .commit();

answered Apr 25 '18 at 13:04

Deˣ

4,191
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24

Charlie · Answer 2 · 2018-04-25T13:23:23.767

0

Once fragment 1 is added to the Activity, I believe you'll need to use getChildFragmentManager() to add additional fragments from a fragment. This method is available to classes that extend a Fragment.

Edit

As you've said you are using getChildFragmentManager(), I would use .beginTransaction().replace(...) instead of .beginTransaction().add(...).

edited Apr 25 '18 at 13:23

answered Apr 25 '18 at 13:07

Charlie

2,876
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sorry. is ```getChildFragmentManager()```. EDITED. my bad – Pak Ho Cheung Apr 25 '18 at 13:07
```.replace``` also return the same result – Pak Ho Cheung Apr 25 '18 at 13:36

score 0 · Answer 3 · answered Apr 25 '18 at 14:20

Try to find the deepest fragment. Then popBackStack right there.

List<Fragment> fs2 = fragments.get(selectedTab).getChildFragmentManager().getFragments().get(0).getChildFragmentManager().getFragments();
FragmentManager f = fragments.get(selectedTab).getChildFragmentManager();
while (fs2.size() > 0) {
    fs2 = fs2.get(0).getChildFragmentManager().getFragments();
    f = f.getFragments().get(0).getChildFragmentManager();
}
f.popBackStack();

call popBackStack result more than one times of onBackPressed

3 Answers3

Edit