react / react/react-native

FlatList with sticky ListHeaderComponent, stickyHeaderIndices, onViewableItemsChanged gives incorrect viewableItems #31109

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Component: FlatList Issue: Author Provided Repro Needs: Triage :mag: Newer Patch Available
Dominant language
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Description

Description

exactly this issue: https://github.com/facebook/react-native/issues/31109. this is still a problem.


using FlatList with stickyHeaderIndices, viewabilityConfigCallbackPairs, and ListHeaderComponent, when scrolling the list onViewableItemsChanged is called. the viewableItems includes items that are behind (not viewable) the sticky list header.

const viewabilityConfig = {
  minimumViewTime: 1000,
  waitForInteraction: true,
  itemVisiblePercentThreshold: 100,
}

const onViewableItemsChanged = React.useCallback(
  ({ viewableItems, changed }) => {
    console.log('viewableItems', viewableItems)
    console.log('changed', changed)
  },
  []
)

const viewabilityConfigCallbackPairs = React.useRef([
  { viewabilityConfig, onViewableItemsChanged },
])

<FlatList
  stickyHeaderIndices={[0]}
  viewabilityConfigCallbackPairs={viewabilityConfigCallbackPairs.current}
  ListHeaderComponent={() => <MyListHeader/>}
/>
React Native Version

0.71.7

Output of npx react-native info

System:
OS: macOS 12.6
CPU: (10) arm64 Apple M1 Pro
Memory: 509.05 MB / 32.00 GB
Shell: 5.8.1 - /bin/zsh
Binaries:
Node: 16.18.1 - ~/.asdf/installs/nodejs/16.18.1/bin/node
Yarn: 1.22.19 - ~/.asdf/installs/nodejs/16.18.1/bin/yarn
npm: 8.19.2 - ~/.asdf/plugins/nodejs/shims/npm
Watchman: Not Found
Managers:
CocoaPods: 1.11.3 - /Users/ty/.asdf/shims/pod
SDKs:
iOS SDK:
Platforms: DriverKit 21.4, iOS 16.0, macOS 12.3, tvOS 16.0, watchOS 9.0
Android SDK: Not Found
IDEs:
Android Studio: 2021.3 AI-213.7172.25.2113.9123335
Xcode: 14.0.1/14A400 - /usr/bin/xcodebuild
Languages:
Java: 11.0.17 - /usr/bin/javac
npmPackages:
@react-native-community/cli: Not Found
react: 18.2.0 => 18.2.0
react-native: 0.71.7 => 0.71.7
react-native-macos: Not Found
npmGlobalPackages:
react-native: Not Found

Steps to reproduce
  1. drag the list so that the 2nd item is the first in the list
  2. observe the viewableItems
Snack, code example, screenshot, or link to a repository

https://snack.expo.io/@tantommy/intelligent-churros

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 by reviewing the linked issue #31109 and reproducing the Snack example with FlatList, stickyHeaderIndices, ListHeaderComponent, and viewabilityConfigCallbackPairs. Verify the behavior while scrolling so the second item is first; done means onViewableItemsChanged reports only items actually visible beneath the sticky header.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript, react-native
Domain
mobile
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
42/100

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