我在ScrollView中有2个FlatList。一旦FlatList进入视图,ScrollView和第二个FlatList就会滞后。我试过只保留一个FlatList,它工作得很顺利。我也使用PureComponent为FlatList
渲染每个单独的项目class HourlyItem extends React.PureComponent {
render() {
return (
<View style={styles.row_2_item}>
<Text style={styles.row_2_item_time}>11:00</Text>
<Image source={{uri: 'icon_sun'}} style={styles.row_2_image1}/>
<Text style={styles.row_2_item_temp}>25°</Text>
<View style={styles.row_2_item_rain_holder}>
<Image source={{uri: 'icon_rain_umbrella'}} style={styles.row_2_item_rain_icon}/>
<Text style={styles.row_2_item_rain_value}>0%</Text>
</View>
</View>
)
}
}
class DailyItem extends React.PureComponent {
render() {
return (
<View style={styles.row_2_item}>
<Text style={styles.row_2_item_time}>THU</Text>
<Image source={{uri: 'icon_cloud_sun'}} style={styles.row_2_image1}/>
<Text style={[styles.row_2_item_temp, {fontFamily: "avenir_medium"}]}>18°/32°</Text>
<View style={styles.row_2_item_rain_holder}>
<Image source={{uri: 'icon_rain_umbrella'}} style={styles.row_2_item_rain_icon}/>
<Text style={[styles.row_2_item_rain_value, {fontFamily: "avenir_medium"}]}>0%</Text>
</View>
</View>
)
}
}
export class HomePage extends Component {
_renderHourlyItem = ({item}) => (
<HourlyItem produto={item.key}/>
);
_renderDailyItem = ({item}) => (
<DailyItem produto={item.key}/>
);
render() {
return (
<View style={styles.container}>
<StatusBar hidden={true}/>
<View style={[styles.mainHeader, {top: this.state.mainHeaderTop}]}>
<Text style={[styles.innerHeaderTemp, {fontSize: 52,lineHeight: 53}]}>28°</Text>
<Text style={styles.innerHeaderLocation}>Kozhikode</Text>
<Text style={styles.innerHeaderDate}>Tuesday, Jan 17</Text>
</View>
<ParallaxScrollView
onScroll={this.handleScroll}
contentBackgroundColor="#fff"
parallaxHeaderHeight={PARALLAX_HEADER_HEIGHT}
backgroundSpeed={10}
fadeOutForeground={false}
renderBackground={() => (
<View key="background">
<View style={styles.iconHolder}>
<Icon style={styles.searchIcon} name="ios-search" size={25} color="rgba(0,0,0,0.75)" />
</View>
<View style={[styles.iconHolder, styles.locationIconHolder]}>
<Icon style={styles.searchIcon} name="ios-pin" size={25} color="rgba(0,0,0,0.75)" />
</View>
<Image source={{uri: 'sun',
width: width,
height: 480}} style={{resizeMode: 'cover'}}/>
</View>
)}
renderForeground={() => (
<View key="parallax-header" style={[styles.parallaxHeader, {borderTopWidth: this.state.slantedHeight}]}>
</View>
)}>
<View style={styles.body}>
<View style={styles.innerHeader}>
<Text style={[styles.innerHeaderTemp, {fontSize: this.state.innerHeaderTempFontSize,
lineHeight: this.state.innerHeaderTempLineHeight}]}>28°</Text>
<Text style={styles.innerHeaderLocation}>Kozhikode</Text>
<Text style={styles.innerHeaderDate}>Tuesday, Jan 17</Text>
</View>
<Text style={styles.summary}>Light rain on Saturday through Tuesday, with temperatures falling to 28°C on Tuesday</Text>
<View style={[styles.boxHolder, {backgroundColor: '#3a99d8', padding: 10}]}>
<FlatList
horizontal={true}
windowSize={5}
showsHorizontalScrollIndicator={false}
data={[{key: 'a'}, {key: 'b'}, {key: 'c'}, {key: 'd'}, {key: 'e'}, {key: 'f'}]}
renderItem={this._renderHourlyItem}
/>
</View>
<View style={[styles.boxHolder, {backgroundColor: '#975db4', padding: 10}]}>
<FlatList
horizontal={true}
windowSize={5}
showsHorizontalScrollIndicator={false}
data={[{key: 'a'}, {key: 'b'}, {key: 'c'}, {key: 'd'}, {key: 'e'}, {key: 'f'}]}
renderItem={this._renderDailyItem}
/>
</View>
</View>
</ParallaxScrollView>
</View>
);
}
正如你所看到的,我的FlatList项目里面有很多视图。如果我删除2或3个视图,性能也会好得多。但不能真正做到这一点,因为UI需要很多观点。
答案 0 :(得分:0)
尝试为React.PureComponent
shouldComponentUpdate
当我在FlatList
内部ScrollView
时,我似乎遇到了性能问题,请尝试将FlatList移出ParallaxScrollView