对道具更改反应重新渲染组件

时间:2020-10-18 10:44:14

标签: reactjs components render

我的Tabbar组件中有一个Tabbar,我可以在其中更改索引道具:

class Tabbar extends Component {

state = {
    index: this.props.index,
    name: this.props.name,
    image: this.props.image
};

changeTabs = () => {
    this.setState({index: this.props.index});
}

render() {
    return (
        <React.Fragment>    
        <div id={this.state.index} className="col">
            <button onClick={this.changeTabs}></button>
        </div>
        </React.Fragment>
        
    );

}

}

export default Tabbar;

然后在其他组件中,我想在更改道具后重新渲染片段。这是我的代码:

import Tabbar from './Tabbar';

class Tabview extends Component {

    constructor(props) {
        super(props);
        this.state = {
            tabs: [
                {index: 0, name: "tab0", image:require('../Assets/profile.svg'),childView: {ProfilePage} },
                {index: 1, name: "tab1", image:require('../Assets/home.svg'),childView: {HomePage}},
                {index: 2, name: "tab2", image:require('../Assets/blog.svg'),childView: {BlogPage}},
              ],
        }
    }

    handleRender = () => {
        this.state.tabs.map(item => {
            if (item.index === this.props.index) {
                return <item.childView/>;
            }
        })
        return <BlogPage/>;
    }


    render() {

        return (
        <div>
            <Header/> 

            {this.handleRender()}
            {this.state.tabs.map(item => 
                        <Tabbar key={item.index} index={item.index} name={item.name} image={item.image}/>
                    )}


    
        </div>
            

        );

    }

}

export default Tabview;

方法“ handleRender”应处理渲染。 我尝试使用“ componentDidMount”或“ componentDidUpdate”,但是我没有用。

我如何使它工作?

提前谢谢!

1 个答案:

答案 0 :(得分:0)

由于这个原因,您不需要在子组件中具有状态 您只需在父级中有一个回调,然后在子级组件中调用它,如下所示。

import React, { Component } from "react";

class Tabbar extends Component {
  render() {
    return (
      <React.Fragment>
        <div id={this.props.index} className="col">
          <button
            onClick={() => this.props.changeTabs(this.props.index)}
          ></button>
        </div>
      </React.Fragment>
    );
  }
}

export default Tabbar;

在父级中,您保持活动索引状态

import Tabbar from "./Tabbar";
import React, { Component } from "react";

class Tabview extends Component {
  constructor(props) {
    super(props);
    this.state = {
      tabs: [
//your tabs
      ],
      activeIndex: 0
    };
  }

  handleRender = () => {
    this.state.tabs.map((item) => {
      if (item.index === this.state.activeIndex) {
        return <item.childView />;
      }
    });
    return <div />;
  };

  render() {
    return (
      <div>
        {this.handleRender()}
        {this.state.tabs.map((item) => (
          <Tabbar
            key={item.index}
            index={item.index}
            name={item.name}
            image={item.image}
            changeTabs={(index) => this.setState({ activeIndex: index })}
          />
        ))}
      </div>
    );
  }
}

export default Tabview;