react / react/react-native

【Android】:Animated.event does not update latest contentOffset.y on onScroll Event When useNativeDriver is set to true

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API: Animated Needs: Triage :mag: Platform: Android
Dominant language
C++
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Avg merge
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Description

Description

I want to implement a stickyHeader component that relies on the scroll event of the scrollView to get the latest contentOffset.y. Then, by listening to the changes in y, I can set the translateY property of the stickyHeader.

However, when the content height of the scrollView changes dynamically, especially when it decreases, using addListener to track the animation value changes, we find that when useNativeDriver is set to true, Animated.event sometimes fails to update the latest contentOffset.y value. The listener callback of Animated.event prints e.nativeEvent.contentOffset.y as the latest value, but printing animatedValue.__getValue still shows the previous value.

Unfortunately, we cannot trigger the animation value change in the listener callback of Animated.event, as that would cause the sticky animation to flicker.

Image

Steps to reproduce
  1. Install the app.
  2. Click on tab1 and scroll the scroll-view content to the bottom.
  3. Click on tab2.
  4. Repeat steps 2 and 3 to reproduce the issue.

I cannot reproduce the issue in the emulator; it only occurs sporadically on a real device.

React Native Version

0.80.1

Affected Platforms

Runtime - Android

Output of npx @react-native-community/cli info
ystem:
  OS: macOS 14.2.1
  CPU: (8) arm64 Apple M3
  Memory: 137.05 MB / 16.00 GB
  Shell:
    version: "5.9"
    path: /bin/zsh
Binaries:
  Node:
    version: 23.10.0
    path: ~/.nvm/versions/node/v23.10.0/bin/node
  Yarn:
    version: 1.22.22
    path: /usr/local/bin/yarn
  npm:
    version: 10.9.2
    path: ~/.nvm/versions/node/v23.10.0/bin/npm
  Watchman:
    version: 2024.10.21.00
    path: /usr/local/bin/watchman
Managers:
  CocoaPods:
    version: 1.15.2
    path: /usr/local/bin/pod
SDKs:
  iOS SDK:
    Platforms:
      - DriverKit 23.4
      - iOS 17.4
      - macOS 14.4
      - tvOS 17.4
      - visionOS 1.1
      - watchOS 10.4
  Android SDK: Not Found
IDEs:
  Android Studio: 2023.3 AI-233.14808.21.2331.11709847
  Xcode:
    version: 15.3/15E204a
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 17.0.11
    path: /usr/bin/javac
  Ruby:
    version: 3.1.0
    path: /Users/didi/.rbenv/shims/ruby
npmPackages:
  "@react-native-community/cli":
    installed: 19.0.0
    wanted: 19.0.0
  react:
    installed: 19.1.0
    wanted: 19.1.0
  react-native:
    installed: 0.80.1
    wanted: 0.80.1
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: true
  newArchEnabled: true
iOS:
  hermesEnabled: Not found
  newArchEnabled: false
Stacktrace or Logs
no logs
MANDATORY Reproducer

https://github.com/yandadaFreedom/reproducer-react-native-0.80.1/tree/bug-animated-event

Screenshots and Videos

The issue is reproduced at the 35-second mark in the video.

https://github.com/user-attachments/assets/f6da6f71-d5a0-410a-b207-2eb9d174d7e5

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the mandatory reproducer and inspect the Android Animated.event path using the native driver, focusing on the dynamic ScrollView content-height change described in the steps. Reproduce on a real device and compare the listener's contentOffset.y with the animated value; done means the latest value is updated reliably without causing sticky-header flicker.

Written by the indexing model from the issue text.

Assessment

Tech stack
android, react-native
Domain
mobile
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Active
Clarity
Needs clarification
Newbie friendliness
35/100

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