Revese FragmentContainerView draw order when fragment is being popped off backstack [139104187]

Fixed

Bug

Status Update

No update yet.

Description

ka...@gmail.com

created issue #1

Aug 8, 2019 10:21AM

Component used: Fragment
Version used: 1.2.0-alpha02
Devices/Android versions reproduced on: Android Emulator API 27

FragmentContainerView always draws entering fragments on top exiting ones. This breaks animations when navigating backwards. Please see attached video and sample project.

Should FragmentContainterView reverse draw order when fragment is being popped off backstack?

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Example.zip

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Comments

il...@google.com <il...@google.com> Aug 8, 2019 04:22PM

Assigned to jb...@google.com.

ap...@google.com <ap...@google.com> #2Aug 22, 2019 06:40PM

Jeremy, is this still an issue? I think the problem was that you had two transitions targeting the same View for the same action (e.g. two Slide() transitions).

jb...@google.com <jb...@google.com> #3Aug 23, 2019 01:49PM

Marked as fixed.

I have a similar issue with plain AnimatorSet:

set.start()
set.pause()
set.setCurrentPlayTime(100)
set.setCurrentPlayTime(0)
set.setCurrentPlayTime(100)
set.resume()

doesn't play animation in resume().

ap...@google.com <ap...@google.com> #4Aug 26, 2019 07:29PM

Should clarify that if I filter out setCurrentPlayTime(0) (or replace it with setCurrentPlayTime(1)) it works well.

Also even with setCurrentPlayTime(0), onAnimationEnd is notified with correct delay (as if the animation has played).

pe...@gmail.com <pe...@gmail.com> #5Dec 10, 2019 03:25PM

@ #4:

I think that is intended for Animator. If you set the currentPlayTime to 0 or the total duration the animator completes. We do some special checks in fragments to handle it.

ka...@gmail.com <ka...@gmail.com> #6Dec 10, 2019 04:01PM

Did some investigation on the Fragment side and it seems like the merged transition is targeting correctly.

Exiting Transition: Slide@aa9288e: tgts(android.widget.LinearLayout{f9add3d})
>>>>> ExitingViews <<<<<
View: android.widget.LinearLayout{f9add3d}
Entering Transition: Slide@35b8af: tgts(android.widget.LinearLayout{b7f24bc})
>>>>> EnteringViews <<<<<
View: android.widget.LinearLayout{b7f24bc}
Final merged transition: TransitionSet@7bc1c45: 
      TransitionSet@e133f9a: 
        Slide@aa9288e: tgts(android.widget.LinearLayout{f9add3d})
      Slide@35b8af: tgts(android.widget.LinearLayout{b7f24bc})
merged transition passed to controlDelayedTransition: TransitionSet@7bc1c45: 
      TransitionSet@e133f9a: 
        Slide@aa9288e: tgts(android.widget.LinearLayout{f9add3d})
      Slide@35b8af: tgts(android.widget.LinearLayout{b7f24bc})

Still digging.

Issue 139104187