IssueTracker

Component used:'androidx.viewpager2:viewpager2:1.1.0-alpha01' Devices/Android versions reproduced on: Several, reliably on OnePlus 8 Pro

If this is a bug in the library, we would appreciate if you could attach:

• Sample project to trigger the issue.
• A screenrecord or screenshots showing the issue (if UI related).

My app has multiple tabs with individual Fragments and associated EditText objects, I am using ViewPager2 to scroll through the different fragments.

From a users perspective the issue is that whenever a user scrolls to another tab and tries to enter or delete data into an EditText the EditText will immediately lose focus. After the EditText is manually re-selected data entry works as expected.

From an application point of view I traced the loss of focus down to the fact that for some reason ScrollEventAdapter.onScrolled get's called with mAdapterState = STATE_IDLE (0) the moment a character is entered or deleted.

Which according to the comments in ScrollEventAdapter.java fires the onPageSelected event which ultimately leads to the loss of focus:

176 public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) 
…
192   } else if (mAdapterState == STATE_IDLE) {
193        // onScrolled while IDLE means RV has just been populated after an adapter has been set.
194        // Contract requires us to fire onPageSelected as well.

I can see that ScrollEventAdapter.onScrolled get's called when flipping through my tabs, but always with mAdapterState > 0.

Steps to reproduce:

1. Manually select a different tab (=Scroll event for ViewPager2 with mAdapterState == 2)
2. Manually add/delete a digit in one of the EditText of the active fragment
3. ViewPager2 ScrollEventAdapter.onScrolled get's fired with mAdapterState == 0
4. ViewPager2 ScrollEventAdapter.onScrolled calls PageSelected which means the Edittext is losing focus.

The screenshot attached shows the situation right after the first digit "1" got entered. The EditText object lost focus and the first ViewPager2 tab got selected.

What makes things even more complicated is that this error occurs 100% on my personal phone (OnePlus 8Pro), fails 8 out of 10 times with the various OS and language versions I use to test in emulators and fails to an unknown extend with my users.

So I guess the bug/question is why is ViewPager2.onScrolled fired the moment I enter/delete a value in the EditText?

I started this topic on StackOverflow https://stackoverflow.com/questions/67344003/edittext-loses-focus-after-first-digit-is-entered but given that I got 0 response I think I might be dealing with a bug rather than a mistake at my end.

Source code and additional screenshots of the app / the tabs and their EditText objects can be found here: https://gitlab.com/toz12/medilog

Happy to provide any additional information required.