react-native-focus-scroll can detect which children are focused when scrolling.
$ npm i react-native-focus-scroll- Add FocusScrollView
- Support horizontal scroll
- Add an android sample
import React, { Component } from 'react'; import { View, Image, } from 'react-native'; import { FocusScrollView } from 'react-native-focus-scroll'; class BeerComponent extends Component { render() { let style; if (this.props.isFocused) { style = {opacity: 1}; } else { style = {opacity: 0.4}; } return ( <Image style={[style, {width: 200, height: 200, position: "absolute"}]} source={{uri: this.props.url}} /> ) } } export default class example extends Component { render() { const urls = [ "https://github.com/c-bata/react-native-focus-scroll/blob/master/example/assets/paulaner.jpg?raw=true", "https://github.com/c-bata/react-native-focus-scroll/blob/master/example/assets/kilkenny.jpg?raw=true", "https://github.com/c-bata/react-native-focus-scroll/blob/master/example/assets/guiness.jpg?raw=true", "https://github.com/c-bata/react-native-focus-scroll/blob/master/example/assets/rokko-yamatanoorochi-ipa.jpg?raw=true", ]; return ( <View style={styles.container}> <FocusScrollView threshold={100}> {urls.map((url, index) => <BeerComponent key={index} imageUrl={url} />)} </FocusScrollView> </View> ); } }All props is propagate to ScrollView wrapped by FocusScrollView .
- type:
integer - required?: optional
- default:
100
If the distance between the center of FocusScrollView and the center of each children exceed a threshold, The item of FocusScrollView is focused.
- type:
function(size, margin) bool {} - required?: optional
To replace the judge whether the child is focused. The default function is below.
whetherIsFocused(size, margin) { const distance = Math.abs((size.y + size.height / 2) - this.getCenterY()); return distance < margin; }