在映射 ReactJS 中显示/隐藏 div

Question

我目前正在学习 ReactJS，我在尝试隐藏/显示 div 时遇到了问题！以下代码正在运行，但是当我单击“了解更多”按钮时，它会隐藏每张卡片上的所有描述，但我想仅在单击它的位置显示/隐藏描述。

import Axios from 'axios';
import React, { useEffect, useState } from 'react';
import JobApplicationList from './JobApplicationList';
import Card from "react-bootstrap/Card";
import ScriptTag from 'react-script-tag';



export default class Home extends React.Component{
    
    constructor(){
        super()
        this.state={
            showMe:true,
            advLists: []
        }
    }

    operation(){
        this.setState({
            showMe:!this.state.showMe
        })
    }

    
    
      componentDidMount() {
        Axios.get(`http://localhost:3001/get/adv`)
          .then(res => {
            const advLists = res.data;
            
            this.setState({ advLists });
          })
      }

      

render(){
    

    return (
        
        <div className="main-page">
            <div className="adv_container">
                {this.state.advLists.map((val, key) => {
                    return (
                        <div className="card_">
                            <Card style={{ width: "100%" }}>
                                <Card.Body>
                                    <Card.Title>{val.compName}</Card.Title>
                                    <Card.Subtitle className="mb-2 text-muted">
                                    {val.city} | {val.compWebsite}
                                    </Card.Subtitle>
                                    <Card.Subtitle className="mb-2 text-muted">
                                    {val.salaire} €
                                    </Card.Subtitle>
                                    { this.state.showMe?
                                        <div className="description">
                                        <Card.Text>{val.description}</Card.Text>
                                        </div>
                                        :null
                                    }
                                    <Card.Link onClick={()=> this.operation()} id="toto" href="#">Learn more</Card.Link>
                                    <Card.Link href="#">Apply</Card.Link>
                                </Card.Body>
                                
                                
                            </Card>
                        </div>
                    );
                })}

            </div>
        </div>
    )
}
}

我有点知道出了什么问题，当我按下按钮时，我会给每张卡显示 showMe 状态，但我不知道如何解决它！ 提前感谢您的帮助。

Answer 1

将初始 showMe 状态设为 null 并将 operation 转换为获取索引以进行切换。如果索引已经保存在 state 中，则设置回 null。

operation(index) {
  this.setState({
    showMe: this.state.showMe === index ? null : index,
  })
}

使用映射索引传递给处理程序并根据showMe 状态检查此索引以显示卡片。

{this.state.advLists.map((val, key) => {
  return (
    <div className="card_">
      <Card style={{ width: "100%" }}>
        <Card.Body>
          <Card.Title>{val.compName}</Card.Title>
          <Card.Subtitle className="mb-2 text-muted">
            {val.city} | {val.compWebsite}
          </Card.Subtitle>
          <Card.Subtitle className="mb-2 text-muted">
            {val.salaire} €
          </Card.Subtitle>
          {this.state.showMe === key && ( // <-- check if index/key matches
            <div className="description">
              <Card.Text>{val.description}</Card.Text>
            </div>
          )}
          <Card.Link
            onClick={() => this.operation(key)} // <-- pass key/index to toggle
            id="toto" href="#"
          >
            Learn more
          </Card.Link>
          <Card.Link href="#">Apply</Card.Link>
        </Card.Body>
      </Card>
    </div>
  );
})}

Answer 2

我可以为您提供有关如何使用 React 类组件切换单个项目的代码模式。

class MyComponent extends React.Component {
  state = { items: [] }; // initial state

  componentDidMount() {
    // fetched data
    this.setState({ items: [{ title: "one" }, { title: "two" }] }); 
  }

  toggleItem = (index) => {
    let items = this.state.items;
    items[index].hidden = !items[index].hidden; // mutating
    this.setState({ items }); // new object triggers re-render
  };

  render() {
    return (
      <ul>
        {this.state.items.map((item, index) => {
          return (
            <li key={index}> {/* remember to use a key */}
              <button onClick={() => this.toggleItem(index)}>toggle</button>

              {!item.hidden && item.title}
            </li>
          );
        })}
      </ul>
    );
  }
}