fix persistent text preview fragment in the background

[parneet-guraya]

Solves: #11836

Before.mp4

After.mp4

What this PR includes?

• Solve the issue by removing this method which was causing the new fragment launch and end up having two same fragments.
• That method was originally added to solve this issue and here's the PR, But now removing this call does not reproduce that same issue also. You can see below -->

issue_not_reproduce.mp4

• Tests written, or not not needed

[parneet-guraya]

Hi, I solved this issue, Here's what was causing it -->

Actual Behaviour ->

• OCFileListFragment which is the main view when launched, starts with fragment transaction (add) without call to addToBackStack(), It means no reverse transaction can happen thus pressing back exits the app (fragment goes in to onStop()).

• While launching PreviewTextStringFragment which opens when clicked upon Readme.md (preview at the top) adapter item , with transaction (replace) with addToBackStack(), so replace cause the OCFileListFragment to Destroy and PreviewTextStringFragment launches.

• This line else if (leftFragment instanceof PreviewTextStringFragment) { createMinFragments(null); } is the main issue first of all it's not calling super.onBackPressed(); which lead to non reversal of replace transaction, so neither the current PreviewTextStringFragment destroys nor OCFileListFragment gets created.

• What createMinFragments(Bundle savedInstanceState) method doing is creating new OCFileListFragment with fragment transaction (add) without addToBackStack(), so no reversals.

• So, now when user click on Preview and it opens up and upon pressing back it does not destroy the Preview Fragment and also create new OCFileListFragment, which shows us the Preview Fragment in the fragment and the new OCFileListFragment on top of it that's why we are seeing persistent Readme file in the background.

But, In fact we should be calling onBackPressed() as well as not calling the createMinFragments(null); since it's creating the new OCFileListFragment and because if we call this one at this point (along with onBackPressed()) then we will end up with two OCFileListFragment showing since one is from reversal transaction and other one is created by function.

And this is what right now we're seeing is the persistent Preview Fragment (due to not calling onBackPressed) and the function creating a new one on top of it.

Thanks!

[github-actions]

Codacy

Lint

Type	master	PR
Warnings	80	80
Errors	0	0

SpotBugs

Category	Base	New
Bad practice	26	26
Correctness	85	85
Dodgy code	434	434
Experimental	2	2
Internationalization	9	9
Malicious code vulnerability	2	2
Multithreaded correctness	9	9
Performance	59	59
Security	18	18
Total	644	644

[github-actions]

APK file: https://www.kaminsky.me/nc-dev/android-artifacts/11937.apk



To test this change/fix you can simply download above APK file and install and test it in parallel to your existing Nextcloud app.

[github-actions]

blue-Light-Screenshot test failed: https://www.kaminsky.me/nc-dev/android-integrationTests/11937-Screenshot-blue-Light-12-59

[parneet-guraya]

Closing as this solution is now part of this #11965 PR.

[github-actions]

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