Created
February 6, 2018 23:37
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import React, { Component } from 'react'; | |
import { View, FlatList, Image } from 'react-native'; | |
import PlaceholderImage from './PlaceholderImage'; | |
export default class App extends Component { | |
state = { | |
data: [ | |
{ id: 0, url: 'https://images.unsplash.com/photo-1467703834117-04386e3dadd8', loaded: false }, | |
{ id: 1, url: 'https://images.unsplash.com/photo-1511971523672-53e6411f62b9', loaded: false }, | |
{ id: 2, url: 'https://images.unsplash.com/photo-1494522358652-f30e61a60313', loaded: false }, | |
], | |
} | |
handleLazyLoad = ({ viewableItems }) => { | |
const newData = this.state.data.map(image => | |
viewableItems.find(({ item }) => item.id === image.id) | |
? { ...image, loaded: true } | |
: image | |
); | |
this.setState({ data: newData }); | |
} | |
renderItem = ({ item }) => ( | |
<View style={{ marginVertical: 20, height: 300, backgroundColor: '#EEE' }}> | |
{ item.loaded && <Image | |
source={{ uri: item.url }} | |
style={{ width: '100%', height: 300 }} | |
/> } | |
</View> | |
); | |
render() { | |
return ( | |
<FlatList | |
data={this.state.data} | |
renderItem={this.renderItem} | |
keyExtractor={item => item.id} | |
onViewableItemsChanged={this.handleLazyLoad} | |
/> | |
); | |
} | |
} |
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