你可以在没有钩子的情况下使用 React Native RefreshControl 吗？

Question

我想在我的 React Native 应用程序中使用 RefreshControl，但是他们的文档中的演示实现使用了钩子，我没有在我的应用程序中使用。当我复制粘贴演示代码时，我收到错误Hooks can only be called inside of the body of a function component。有没有办法让我在不将我的组件转换为函数组件的情况下使用这个库？

Answer 1

您可以在基于类的组件中使用RefreshControl，从而避免挂钩。这是一个例子：

import React, { Component } from 'react';
import { StyleSheet, View, ListView, RefreshControl, Text } from 'react-native'


class RefreshControlExample extends Component {
  constructor () {
    super()
    this.state = {
      refreshing: false,
      dataSource: new ListView.DataSource({
        rowHasChanged: (row1, row2) => row1 !== row2 }),
      cars : [
        {name:'BMW',color:'White'},
        {name:'Mercedes',color:'Green'}
      ]
    }
  }

   componentWillMount(){
     this.setState({ dataSource:
       this.state.dataSource.cloneWithRows(this.state.cars) })
   }

  render() {
    return (
      <View style={{flex:1}}>
        <ListView
          refreshControl={this._refreshControl()}
          dataSource={this.state.dataSource}
          renderRow={(car) => this._renderListView(car)}>
        </ListView>
      </View>
    )
  }

  _renderListView(car){
    return(
      <View style={styles.listView}>
        <Text>{car.name}</Text>
        <Text>{car.color}</Text>
      </View>
    )
  }

  _refreshControl(){
    return (
      <RefreshControl
        refreshing={this.state.refreshing}
        onRefresh={()=>this._refreshListView()} />
    )
  }

  _refreshListView(){
    //Start Rendering Spinner
    this.setState({refreshing:true})
    this.state.cars.push(
      {name:'Fusion',color:'Black'},
      {name:'Yaris',color:'Blue'}
    )
    //Updating the dataSource with new data
    this.setState({ dataSource:
        this.state.dataSource.cloneWithRows(this.state.cars) })
    this.setState({refreshing:false}) //Stop Rendering Spinner
  }

}

const styles = StyleSheet.create({

  listView: {
    flex: 1,
    backgroundColor:'#fff',
    marginTop:10,
    marginRight:10,
    marginLeft:10,
    padding:10,
    borderWidth:.5,
    borderColor:'#dddddd',
    height:70
  }

})

export default RefreshControlExample;