react / react/react-native

Unmounting list header component while applying maintainVisibleContentPosition to flatlist renders white space in place of header compoent on Ios

Aperta
#42,905 3 commenti 3 reazioni 0 assegnatari Vedi su GitHub

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Component: FlatList Issue: Author Provided Repro Needs: Triage :mag: Platform: iOS
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Descrizione

Description

If a flatlist with a maintainVisibleContentPosition prop set has a header list component that is unmounted then the header component unmounts but the list does not scroll to the first element and instead renders white space.

Here is the source code also available as 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 [isHeaderShown, setIsHeaderShown] = useState(true);
  return (
    <SafeAreaView style={styles.container}>
      <FlatList
        maintainVisibleContentPosition={{
          minIndexForVisible: 0,
          autoscrollToTopThreshold: 0,
        }}
        ListHeaderComponent={
          isHeaderShown ? (
            <View style={{padding: 128, backgroundColor: 'red'}} />
          ) : null
        }
        data={Array.from({length: 30})
          .fill(0)
          .map((_, index) => `Item ${index}`)}
        renderItem={({item}) => <Item title={item} />}
      />
      <Button
        title="press me"
        onPress={() => {
          setIsHeaderShown(prev => !prev);
        }}
      />
    </SafeAreaView>
  );
};

const styles = StyleSheet.create({
  container: {
    flex: 1,
    marginTop: StatusBar.currentHeight || 0,
  },
  item: {
    backgroundColor: '#f9c2ff',
    padding: 20,
    marginVertical: 8,
    marginHorizontal: 16,
  },
  title: {
    fontSize: 32,
  },
});

export default App;
Steps to reproduce
  1. click on the press me button and notice how there is white space on ios and the list does not scroll, but works fine on android
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/maintainvisiblecontentposition-header-top

Screenshots and Videos

https://github.com/facebook/react-native/assets/80689446/c563b30a-b61d-4822-9e77-0820b25756a7

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  4. Apri una pull request che faccia riferimento al numero della issue.

Direzione di ricerca

Inizia dal reproducer Snack collegato e dal comportamento di FlatList maintainVisibleContentPosition su iOS. Traccia la gestione su iOS di una ListHeaderComponent smontata condizionalmente, quindi verifica che l'attivazione/disattivazione dell'header rimuova lo spazio bianco e faccia scorrere fino al primo elemento senza causare regressioni nel comportamento su Android.

Scritto dal modello di indicizzazione a partire dal testo della issue.

Valutazione

Stack tecnologico
ios, react-native
Ambito
mobile
Tipo di issue
Bug
Difficoltà
4/5
Tempo stimato
3-5 giorni
Stato di attività
Ferma
Chiarezza
Abbastanza chiara
Idoneità per principianti
35/100

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