FlatList with sticky ListHeaderComponent, stickyHeaderIndices, onViewableItemsChanged gives incorrect viewableItems #31109
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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
- drag the list so that the 2nd item is the first in the list
- observe the viewableItems
Snack, code example, screenshot, or link to a repository
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- 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