子组件修改父组件的状态,在开发中非常常见,下面列举了几种方式。
DeviceEventEmitter可以跨组件,跨页面进行数据传递,还有一些状态的修改。http://www.jianshu.com/p/c6991a241b4f
兄弟组件可以进行修改,所谓兄弟组件,就是说同一个页面,有两个组件,组件A,组件B,组件A的状态的变化,可以导致组件B的状态变化,有两种方式。第一种,使用DeviceEventEmitter跨组件通信。第二种,在页面内定义一个State,组件A,使用props属性引入,操作组件A,修改页面内的State,然后,组件B,也是引入页面内的State,所有,当组件A状态变化时,修改页面的State,重新Render,然后,更新组件B,组件B进行Render。
二: Coding
新建三个组件:分别为PostCallMsgAndMsg,PostCallMsg,PostMsg;
在Msg进行使用。
import React, { Component } from 'react'; import { AppRegistry, StyleSheet, Text, View, DeviceEventEmitter } from 'react-native'; import PostMsg from './PostMsg' import PostCallMsg from './PostCallMsg' import PostCallMsgAndMsg from './PostCallMsgAndMsg' export default class Msg extends Component { constructor(props){ super(props); this.state={ listenerMsg:'listenerMsg', callMsg:'callMsg', callMsgAndMsg:'callMsgAndMsg' } } componentDidMount() { //注意addListener的key和emit的key保持一致 this.msgListener = DeviceEventEmitter.addListener('Msg',(listenerMsg) => { this.setState({ listenerMsg:listenerMsg, }) }); } componentWillUnmount() { //此生命周期内,去掉监听 this.msgListener&&this.msgListener.remove(); } render() { return ( <View style={styles.container}> <Text>第一种方式 DeviceEventEmitter:</Text> <Text>{this.state.listenerMsg}</Text> <PostMsg /> <Text>第二种方式 CallBack:</Text> <Text>{this.state.callMsg}</Text> <PostCallMsg onChangeMsg={ this.onMsgByCall }/> <Text>第三种方式 CallBack有参数:</Text> <Text>{this.state.callMsgAndMsg}</Text> <PostCallMsgAndMsg onChangeMsg={(msg)=>{ this.onMsgByCallAndMsg(msg) } }/> </View> ); } onMsgByCall=()=>{ this.setState({ callMsg:'通过CallBack修改父组件状态值' }) } onMsgByCallAndMsg=(msg)=>{ this.setState({ callMsgAndMsg:msg }) } } const styles = StyleSheet.create({ container: { flex: 1, justifyContent: 'center', alignItems:'center', }, });
import React, { Component } from 'react'; import { AppRegistry, StyleSheet, Text, View, TouchableOpacity, } from 'react-native'; export default class PostCallMsgAndMsg extends Component { render() { return ( <View style={styles.container}> <View style={styles.viewLine}/> <TouchableOpacity onPress={this._postMsgByCallBack}> <Text>PostCallMsgAndMsg</Text> </TouchableOpacity> </View> ); } _postMsgByCallBack=()=>{ if(this.props.onChangeMsg){ this.props.onChangeMsg('通过PostCallMsgAndMsg来传递属性'); } } } const styles = StyleSheet.create({ container: { justifyContent: 'center', alignItems: 'center', marginBottom:20, }, });
import React, { Component } from 'react'; import { AppRegistry, StyleSheet, Text, View, TouchableOpacity, } from 'react-native'; export default class PostCallMsg extends Component { render() { return ( <View style={styles.container}> <View style={styles.viewLine}/> <TouchableOpacity onPress={this._postMsgByCallBack}> <Text>Callback</Text> </TouchableOpacity> </View> ); } _postMsgByCallBack=()=>{ if(this.props.onChangeMsg){ this.props.onChangeMsg(); } } } const styles = StyleSheet.create({ container: { justifyContent: 'center', alignItems: 'center', marginBottom:20, }, });
import React, { Component } from 'react'; import { AppRegistry, StyleSheet, Text, View, TouchableOpacity, DeviceEventEmitter, } from 'react-native'; export default class PostMsg extends Component { render() { return ( <View style={styles.container}> <TouchableOpacity onPress={this._postMsgByListener}> <Text>DeviceEventEmitter</Text> </TouchableOpacity> </View> ); } _postMsgByListener=()=>{ DeviceEventEmitter.emit('Msg','此消息来自于子组件,DeviceEventEmitter父组件进行修改和状态变化'); } } const styles = StyleSheet.create({ container: { justifyContent: 'center', alignItems: 'center', marginBottom:20, }, });