Starting a postponed transition instantly cancels the enter transition [170022857]

Fixed

Bug

Status Update

No update yet.

Description

[Deleted User]

created issue #1

Oct 4, 2020 07:31PM

Component used: Fragment
Version used: 1.3.0-beta01
Devices/Android versions reproduced on: Google Pixel 4 XL

There are some key components here:

It only happens if you are using Fragments 1.3
It only happens if you are using androidx.transition 1.4 (not 1.2)
It only happens if you call startPostponedEnterTransition instantly after postponing

The effect is really noticeable when using the MDC transitions since they are currently not handling cancelations gracefully so it leaves the target view with alpha 0.

One fix is to always wait calling startPostponedEnterTransition at least one frame by posting to a handler or using yield() with Coroutines.

You may wonder why I'm calling start instantly and it's because the data is cached:

postponeEnterTransition(500, TimeUnit.MILLISECONDS)
viewLifecycleOwner.lifecycleScope.launch {
    // Imagine that loadData() does not suspend because the data is cached
    val data = loadData()
    setupViews(data)
    // Uncommenting this will mitigate the issue
    // yield()
    startPostponedEnterTransition()
}

broken-with-postpone.mp4

68 KB

Download

working-without-postpone.mp4

294 KB

Download

TestFragmentTransitions.zip

145 KB

Download

Comments

jb...@google.com <jb...@google.com> Oct 5, 2020 06:20PM

Assigned to jb...@google.com.

ap...@google.com <ap...@google.com> #2Nov 20, 2020 08:14PM

Project: platform/frameworks/support
Branch: androidx-main

commit 57ca221882695bd6a52549f4d9ea3b812e6fe87c
Author: Simon Schiller <simonschiller@users.noreply.github.com>
Date: Mon Mar 22 16:09:30 2021

[GH] [FragmentStrictMode] Detect <fragment> tag usage

## Proposed Changes

- Detect `<fragment>` tag usage inside XML layouts

## Testing

Test: See `FragmentStrictModeTest#detectFragmentTagUsage`

## Issues Fixed

Fixes: 153738235

This is an imported pull request from

https://github.com/androidx/androidx/pull/141.

Resolves #141
Github-Pr-Head-Sha: 4ea052596e4341b9f11bcf335e2bc38045a91f19
GitOrigin-RevId: 62e7487aa4874eef6bb556490e193717cf937251
Change-Id: Iae48578e85e4e4897f806d7ade2e2a660adf9479

M fragment/fragment/api/public_plus_experimental_current.txt
M fragment/fragment/api/restricted_current.txt
M fragment/fragment/src/androidTest/java/androidx/fragment/app/strictmode/FragmentStrictModeTest.kt
M fragment/fragment/src/main/java/androidx/fragment/app/FragmentLayoutInflaterFactory.java
M fragment/fragment/src/main/java/androidx/fragment/app/strictmode/FragmentStrictMode.java
A fragment/fragment/src/main/java/androidx/fragment/app/strictmode/FragmentTagUsageViolation.java

https://android-review.googlesource.com/1649748

jb...@google.com <jb...@google.com> #3Nov 20, 2020 09:36PM

Marked as fixed.

This has been fixed internally and will be available in the Fragment 1.3.0-beta02 release.

You can verify this by following the snapshot instructions with build id 6986935 and switching your fragment dependency to 1.3.0-SNAPSHOT.

Issue 170022857

Description

Issue summary

Comments

jb...@google.com <jb...@google.com> Oct 5, 2020 06:20PM

ap...@google.com <ap...@google.com> #2Nov 20, 2020 08:14PM

jb...@google.com <jb...@google.com> #3Nov 20, 2020 09:36PM

Add comment

Issue metadata