How to reuse a fragment

Question

When I replace a fragment, it gets destroyed. I tried to create the fragment in activity's onCreate and hold its reference in the activity and use it when I "re show" or "reopen" it by calling replace with the reference, but that did not help and the fragment got destroyed (when replaced by another fragment) and recreated. What should be the solution?

What I'm trying to achieve is something like say WhatsApp where fragments should not be destroyed when not visible, except I'm not using a sliding gesture but rather regular buttons.

Thanks.

normally fragments should not be held in memory, and should be re-created. — Vladyslav Matviienko, Aug 21 '18 at 12:02
I think the solution is to save the state of the fragment and re-create it when needed. This way the fragment doesn't have to stay in memory while in background. — Lars, Aug 21 '18 at 12:04
also why do you think that they are not destroyed in WhatsApp? — Vladyslav Matviienko, Aug 21 '18 at 12:06
Fragments like Whatsapp never gets destroyed because they are a part of ViewPager. Try something like that to prevent it from being destroyed. — Ümañg ßürmån, Aug 21 '18 at 12:07
post what you have tried so far. (Source code) That will be more helpful — NirmalCode, Aug 21 '18 at 12:11

score 6 · Answer 1 · answered Aug 21 '18 at 12:13

You need to use addToBackStack() to remeber the fragment transaction like below:-

FragmentA fragmentA = new FragmentA();
getFragmentManager().beginTransaction()
    .replace(R.id.YOUR_CONTENT,fragmentA,"YOUR_TARGET_FRAGMENT_TAG")
    .addToBackStack("YOUR_SOURCE_FRAGMENT_TAG").commit();

And u can check the fragment is it already present in the stack or not like below

Fragment fragment = getFragmentManager().findFragmentByTag("YOUR_TARGET_FRAGMENT_TAG");

 if (fragment!=null && fragment instanceof FragmentA) {
   //you are good to go, do your logic   
    }

score 0 · Answer 2 · edited Aug 28 '18 at 07:52

0

Use a bundle to save state information and restore it perhaps within onCreate()?

edited Aug 28 '18 at 07:52

Ravindra Kushwaha

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answered Aug 21 '18 at 12:07

James

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score 0 · Answer 3 · answered Aug 21 '18 at 12:07

0

FragmentTransaction.replace(): Replace an existing fragment that was added to a container.

So this removes the Fragment from the stack.

Use FragmentTransaction.addToBackStack() to add the Fragment on top of another(s) (the stack).

answered Aug 21 '18 at 12:07

shkschneider

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score 0 · Answer 4 · answered Aug 21 '18 at 14:20

The solution is ViewPager with PagerAdapter, more specifically to my case is FragmentPagerAdapter.

Implementation of PagerAdapter that represents each page as a Fragment that is persistently kept in the fragment manager as long as the user can return to the page. This version of the pager is best for use when there are a handful of typically more static fragments to be paged through, such as a set of tabs. The fragment of each page the user visits will be kept in memory, though its view hierarchy may be destroyed when not visible.

https://developer.android.com/reference/android/support/v4/app/FragmentPagerAdapter

I have dealt with it before very very long ago, though I didn't consider it because back then I used it with TabLayout and I thought they were tightly coupled.

How to reuse a fragment

4 Answers4