maintainVisibleContentPosition incorrectly autoscrolls on ios
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Description
Description
What I want is for flatlist to maintain its position if the offset is larger than 10, otherwise automatically scroll to new content, so I am using the maintainVisibleContentPosition with values of { minIndexForVisible: 0, autoscrollToTopThreshold: 10, }. Now this works correctly on android but not on ios.
Here is a small reproducible or its snack:
import React, {useState} from 'react';
import {
SafeAreaView,
View,
FlatList,
StyleSheet,
Text,
StatusBar,
Button,
} from 'react-native';
type ItemProps = {title: string};
const Item = ({title}: ItemProps) => (
<View style={styles.item}>
<Text style={styles.title}>{title}</Text>
</View>
);
const App = () => {
const [data, setData] = useState([1, 2, 3, 4, 5, 6, 7, 8, 9]);
const addToTop = () => {
setData([data[0] - 1, ...data]);
};
const removeFromTop = () => {
const [_, ...rest] = data;
setData(rest);
};
return (
<SafeAreaView style={styles.container}>
<FlatList
maintainVisibleContentPosition={{ minIndexForVisible: 0, autoscrollToTopThreshold: 10, }}
data={data}
renderItem={({item}) => <Item title={`Item ${item}`} />}
keyExtractor={item => item.toString()}
/>
<Button title="add to top" onPress={addToTop} />
<Button title="remove from top" onPress={removeFromTop} />
</SafeAreaView>
);
};
const styles = StyleSheet.create({
container: {
flex: 1,
marginTop: StatusBar.currentHeight || 0,
},
item: {
backgroundColor: '#f9c2ff',
padding: 20,
marginVertical: 8,
marginHorizontal: 16,
height: 480,
},
title: {
fontSize: 32,
},
});
export default App;
Steps to reproduce
- Copy the repro above to some rn project
- Scroll to half of the first element, then press
addToTop, on android position will be maintained which is correct but on ios it autoscrolls.
React Native Version
0.73.4
Affected Platforms
Runtime - iOS
Output of npx react-native info
System:
OS: macOS 14.1.2
CPU: (16) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
Memory: 2.57 GB / 16.00 GB
Shell:
version: "5.9"
path: /bin/zsh
Binaries:
Node:
version: 18.17.1
path: ~/.nvm/versions/node/v18.17.1/bin/node
Yarn:
version: 1.22.19
path: ~/.nvm/versions/node/v18.17.1/bin/yarn
npm:
version: 9.6.7
path: ~/.nvm/versions/node/v18.17.1/bin/npm
Watchman:
version: 2024.01.22.00
path: /usr/local/bin/watchman
Managers:
CocoaPods:
version: 1.15.0
path: /Users/ramiel/.rbenv/shims/pod
SDKs:
iOS SDK:
Platforms:
- DriverKit 23.2
- iOS 17.2
- macOS 14.2
- tvOS 17.2
- visionOS 1.0
- watchOS 10.2
Android SDK: Not Found
IDEs:
Android Studio: 2023.1 AI-231.9392.1.2311.11076708
Xcode:
version: 15.2/15C500b
path: /usr/bin/xcodebuild
Languages:
Java:
version: 11.0.15
path: /usr/local/opt/openjdk@11/bin/javac
Ruby:
version: 2.7.6
path: /Users/ramiel/.rbenv/shims/ruby
npmPackages:
"@react-native-community/cli": Not Found
react:
installed: 18.2.0
wanted: 18.2.0
react-native:
installed: 0.73.4
wanted: 0.73.4
react-native-macos: Not Found
npmGlobalPackages:
"*react-native*": Not Found
Android:
hermesEnabled: true
newArchEnabled: false
iOS:
hermesEnabled: true
newArchEnabled: false
### Stacktrace or Logs
```text
No Stacktrace or Logs
Reproducer
https://snack.expo.dev/@ramiel99/spunky-green-peanut
Screenshots and Videos
https://github.com/facebook/react-native/assets/80689446/456e98f1-d5a8-4253-9a53-9b8d08e61426
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 running the linked Snack on iOS and Android and exercise FlatList's maintainVisibleContentPosition with the add-to-top and remove-from-top actions. Trace the FlatList behavior around the reported threshold, then verify that iOS maintains the offset when it is over 10 and only autoscrolls when it is within the threshold, matching Android.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- ios, 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