ReactNative ListView inconsistent separator lines - react-native-listview

Question

On Android 4.4, ListView separator lines are inconsistent in thickness, and some do not render.
I can't see how this can be a code issue, this is how I render them:
separator: {
height: 1,
backgroundColor: 'grey',
}
...
<ListView
renderSeparator={(sectionID, rowID) =>
<View key={`${sectionID}-${rowID}`} style={styles.separator} />
}
.../>
Here is a screenshot of a View with this problem:
This issue does not happen on iOS or Android 6.
Anyone had this problem before?
Update
I did a test, this is not Android4 issue. It happens on all API version when running on Nexus One device (in android emulator)

Answer 1

I had this issue on iOS and worked around it by adding a hairline margin, like so:
<View
style={{
...styles,
borderWidth: StyleSheet.hairlineWidth,
margin: StyleSheet.hairlineWidth,
}}
>
{// ...row content}
</View>

Answer 2

Just give the height:hairlineWidth in style

Answer 3

I had the same issue and solved changing the view height from a number to StyleSheet.hairlineWidth as some folks said before. Trying to be more visual/specific:
Before:
renderItemSeparator() {
return (
<View style={{ height: .2, backgroundColor: 'rgba(0,0,0,0.3)' }} />
);
}
After:
renderItemSeparator() {
return (
<View style={{ height: StyleSheet.hairlineWidth, backgroundColor: 'rgba(0,0,0,0.3)' }} />
);
}

Answer 4

Actually there is no fix. It's RN "render-canvas-bug".
But I found hack solution.
<ListView
style={Style.listView}
dataSource={data}
renderRow={(data) => this._renderRow(data)}
/>`
Style.listView: {
backgroundColor: '#fff',
}, // or another backgroundColor you need
Then:
_renderRow(goods) {
return (
<View key={'goods_' + goods.id} style={Style.listView_item}>
<TouchableOpacity or View or ...
style={[Style.flex, Style.flexRow, Style.separatorRow, Style.u_paddingVerticalS, Style.u_middle]}
onPress={() => this._xyz(goods)}>
<View>
<AppFont>{goods.name}</AppFont>
</View>
</TouchableOpacity or View or ...>
</View>
);
}
Only important TouchableOpacity style is Style.separatorRow to render your separator. This style should be inside listView_item, where you can use another styles.
listView: {
backgroundColor: '#fff',
},
listView_item: {
paddingHorizontal: em(1.5),
},
flex: {
flex: 1,
},
flexRow: {
flexDirection: 'row',
},
separatorRow: {
marginBottom: 1,
borderBottomWidth: 1,
borderBottomColor: Colors.canvasColor,
},
You can use StyleSheet.hairlineWidth instead of 1 but it's not a must.

Answer 5

I reported it on GitHub
My workaround was to style the containing view and text like this:
const styles = StyleSheet.create({
rowViewContainer: {
flex: 1,
paddingRight: 15,
paddingTop: 13,
paddingBottom: 13,
borderBottomWidth: 0.5,
borderColor: '#c9c9c9',
flexDirection: 'row',
alignItems: 'center',
},
rowText: {
marginLeft: 15,
},
});
This is the ListView:
<ListView
dataSource={this.state.dataSource}
renderRow={(data) => <View style={styles.rowViewContainer}>
<Text style={styles.rowText}>
{data.bb_first_name}
</Text>
</View>}
/>
Looks nice:

Answer 6

This happens because you have empty rows in your data source. You can style your separators to see it
To avoid this just filter your data.

Answer 7

I faced the same issue when trying to render a Divider with a width of 0.5.
It rendered properly on devices with pixel ratio of 2 (e.g. iPhone SE 2nd gen.) but rendered random width on devices with pixel ratio of 3 (e.g. iPhone 12).
As suggested by other answers, using Stylesheet.hairlineWidth fixes the random width issue but the problem was that the width was thinner than 0.5 on devices with pixel ratio of 3.
So this fixed my problem:
import { PixelRatio, View } from 'react-native';
...
export const Divider = () => {
const width = PixelRatio.roundToNearestPixel(0.5);
...
return <View style={{ width }} ... />
}