反应HOC并对此失去参考

时间:2019-02-18 22:32:29

标签: reactjs react-native this

我正在尝试了解和使用带有React和Redux的HOC。我有以下设置。我将有多个使用临时按钮并传递自己的onClick的按钮。并想知道:

a。这是HOC模式的好用法吗?

b。通过在FooterButton的渲染功能中进行此设置,this引用的DesignatedWorkerGlobalScope以及HomeButton中的iconHeigh,iconWidth和iconColor变为未定义或意外值。

任何建议将不胜感激。

import React from 'react';
import { View, Text, TouchableOpacity } from 'react-native';

import { connect } from 'react-redux';
import { compose } from 'redux';

import { getColors, getStylesheet} from "../../styles/StyleManager";

const FooterButtonWrapper = (FooterButtonWrapped, onClick) => { 
    return class FooterButton extends React.Component {

        constructor(props) {
            super(props);

            this.state = {
                Theme: getStylesheet(),
                colors: getColors()
            }            
        }

        _onClick = () => {
            onClick(this.props.dispatch);
        }

        render() {            
            const { Theme, colors } = this.state;

            return(                
                <TouchableOpacity onPress={this._onClick}>
                    <FooterButtonWrapped iconWidth={15} iconHeight={15}  iconColor={"white"}/>            
                </TouchableOpacity>
            )
        }

    }
}

const mapStateToProps = (state, ownProps) => ({});


const composeFooterButton = compose(
    connect(mapStateToProps),
    FooterButtonWrapper 
);

export default composeFooterButton;

,然后是使用它的按钮:

import React from 'react'; import { View, Text } from 'react-native'; import { push as gotoRoute } from 'react-router-redux'; import { FooterButtonWrapper } from './'; import { Home } from '../../assets'; const HomeButton = ({iconHeight, iconWidth, iconColor}) => ( <View> <Home width={ iconWidth } height={ iconHeight } color={ iconColor }/> <View><Text>Home</Text></View> </View> ); const _onClick = dispatch => { dispatch( gotoRoute( '/' )); } export default FooterButtonWrapper(HomeButton, _onClick);

1 个答案:

答案 0 :(得分:0)

发生这种情况是因为您使用

const composeFooterButton = compose(
    connect(mapStateToProps),
    FooterButtonWrapper 
);

export default composeFooterButton;

用于HOC功能而不是组件。

composeconnect都可以包装您的组件。 因此,您的HOC可能是:

import React from 'react';
import { View, Text, TouchableOpacity } from 'react-native';

import { connect } from 'react-redux';
import { compose } from 'redux';

import { getColors, getStylesheet } from '../../styles/StyleManager';

export default function FooterButtonWrapper(FooterButtonWrapped, onClick) {
  class FooterButton extends React.Component {
    constructor(props) {
      super(props);

      this.state = {
        Theme: getStylesheet(),
        colors: getColors(),
      };
    }

    _onClick = () => {
      onClick(this.props.dispatch);
    };

    render() {
      const { Theme, colors } = this.state;

      return (
        <TouchableOpacity onPress={this._onClick}>
          <FooterButtonWrapped
            iconWidth={15}
            iconHeight={15}
            iconColor={'white'}
          />
        </TouchableOpacity>
      );
    }
  }
  const mapStateToProps = (state, ownProps) => ({});


  return connect(mapStateToProps)(FooterButton);  
}