Question

所有

我遇到了一个在函数中未定义的this.props的问题。我想我忘记了某个地方，但我找不到。

在我的“页面”中：

进口：

import React, { Component } from 'react';'''''
import { View, Text, Image } from 'react-native';
import { Button } from '../components';
import { Container, Content, Item, Input } from 'native-base';
import { connect } from 'react-redux';
import {increment, decrement } from '../actions';

功能声明：

class EltTestPage extends Component {

constructor(props) {
    super(props);
}
increment(){
   console.log("DEBUG : props in function :"+this.props);
   this.props.increment();
}
decrement(){
   this.props.decrement();
 }

渲染：

render() { 
    const {elt} = this.props;
    console.log("DEBUG : props in render :"+this.props);
    return (
      <Container>
        <Content>
          <View>
            <Item>
              <Button 
                  onPress={this.increment} 
                  style={{width: 30, height: 30}}>
                  <Text>+</Text>
              </Button>
              {//many other things here}
            </Item>
          </View>
        </Content>
      </Container>
    );
}

连接

export default connect(mapStateToProps, {increment,decrement } ) ( EltTestPage );

在我的操作文件中：

import { Actions } from 'react-native-router-flux';

import {
   INCREMENT_NBRE,
   DECREMENT_NBRE
} from './types';


export const increment=()=>{
  return {
    type: INCREMENT_NBRE,
  };
 }

export const decrement=()=> {
    return {
       type: DECREMENT_NBRE,
    };
 }

在Actions / index.js中添加

console.log中的结果

03-29 10:21:42.613 4210-6713/? I/ReactNativeJS: DEBUG : props in render :
03-29 10:21:42.613 4210-6713/? I/ReactNativeJS: { screenProps: undefined,
                                              navigation: 
                                               { dispatch: [Function],
                                                 state: 
                                                  { routeName: 'eltTest',
                                                    key: 'Init-id-1522318902557-0',
                                                    params: 
                                                     { title: 'composant',
                                                       hideNavBar: true,
                                                       panHandlers: null,
                                                       init: true } },
                                                 goBack: [Function: goBack],
                                                 navigate: [Function: navigate],
                                                 setParams: [Function: setParams] },
                                              title: 'composant',
                                              hideNavBar: true,
                                              panHandlers: null,
                                              init: true,
                                              name: 'eltTest',
                                              elt: { nbre: 20, nbreTxt: '20' },
                                              increment: [Function],
                                              decrement: [Function] }


03-29 10:21:43.749 4210-6713/? I/ReactNativeJS: DEBUG : props in function :
03-29 10:21:43.749 4210-6713/? I/ReactNativeJS: undefined
03-29 10:21:43.750 4210-6713/? E/ReactNativeJS: undefined is not an object (evaluating 'this.props.increment')

Error on the simulator

React-native Redux：this.props undefined

0 个答案: