Inconsistent separator lines

[OtavioStasiak]

Description

The thickness of the separator lines in FlatList is inconsistent on android. Here's another issue related to the separator: GitHub Issue.

Steps to reproduce

Add a separator to a FlatList with hairlineWidth or 1.

React Native Version

0.73.6

Affected Platforms

Runtime - Android

Output of npx react-native info

Expo 51 from snack.

Stacktrace or Logs

import React from 'react';
import {
  SafeAreaView,
  View,
  FlatList,
  StyleSheet,
  Text,
  StatusBar,
} from 'react-native';

const DATA = [...Array(100).keys()]

const Separator = () => <View style={{ height: StyleSheet.hairlineWidth, backgroundColor: '#000' }} />

const Item = ({title}) => (
  <View style={styles.item}>
    <Text style={styles.title}>{title}</Text>
  </View>
);

const App = () => {
  return (
    <SafeAreaView style={styles.container}>
      <FlatList
        data={DATA}
        renderItem={({item}) => <Item title={item} />}
        ItemSeparatorComponent={Separator}
      />
    </SafeAreaView>
  );
};

const styles = StyleSheet.create({
  container: {
    flex: 1,
    marginTop: StatusBar.currentHeight || 0,
  },
  item: {
    backgroundColor: 'white',
    padding: 12,
  },
  title: {
    fontSize: 20,
  },
});

export default App;

Reproducer

https://snack.expo.dev/@diegolmello/f6c27a

Screenshots and Videos

[react-native-bot]

⚠️

Newer Version of React Native is Available!

ℹ️

You are on a supported minor version, but it looks like there's a newer patch available - 0.73.10. Please upgrade to the highest patch for your minor or latest and verify if the issue persists (alternatively, create a new project and repro the issue in it). If it does not repro, please let us know so we can close out this issue. This helps us ensure we are looking at issues that still exist in the most recent releases.

[react-native-bot]

⚠️

Newer Version of React Native is Available!

ℹ️

You are on a supported minor version, but it looks like there's a newer patch available - undefined. Please upgrade to the highest patch for your minor or latest and verify if the issue persists (alternatively, create a new project and repro the issue in it). If it does not repro, please let us know so we can close out this issue. This helps us ensure we are looking at issues that still exist in the most recent releases.

[shubhamguptadream11]

@OtavioStasiak I tested this on multiple real android devices.
It seems that it is reproducible on emulators only.

Are you able to repro this on any real device?

Device used:

• VIVO V2125
• OPPO CPH2185
• REALME RMX2081
• REDMI k20 pro
• REDMI 9A

[iankberry]

Fwiw I can easily reproduce this on my Pixel 7. Using a FlatList with the following separator component:

<View style={{
    borderBottomWidth: StyleSheet.hairlineWidth,
    borderBottomColor: '#54545657',
}} />

I included a second screenshot with a red background to show that it's bleeding through even though the border is a light gray.