条件渲染 + 反应

时间:2021-02-19 00:34:44

标签: reactjs

我尝试制作一个保持先前状态的方法,并在单击时变回先前的状态。但是我检查了该方法是否有效,并且它在正确和错误之间正确转换。

然而,当我在 className 中执行三元运算符时,它保持为真值,并且不允许我在两个类之间切换。第一个是常规边框,第二个具有绝对位置,并带有复选标记以表明它已被选中。即使当我检查开发工具时,“复选标记”是 className 但 onClick 没有任何变化...

import React from 'react';
import './Questions.css'
import girl_sweat from './girl_sweat.jpg'

class Questions extends React.Component {
    constructor(props){
        super(props);
        this.state = {
            isChoiceClicked: false
        }
        this.handleChoice = this.handleChoice.bind(this);
    }

  
    handleChoice(){
    this.setState(prevState => ({isChoiceClicked: !prevState.isChoiceClicked}));
    }

 

    render(){
        const isChoiceClicked = this.state;

        return <div className="banner_column">
        <div className="banner_column_1"><img src={girl_sweat}/></div>
        <div className="banner_column_2"><div className="survey_enter"><h2 className="title">What are you interested in?</h2>
                <p className="description">Select up to <strong>3 areas</strong></p>
                <div className="choices">
                <div className={`choice_container ${isChoiceClicked ? 'checkmark': 'null'}`} onChange={this.handleChoice}><h5>Yoga</h5><p className="activities">Vinyasa, Ashtanga, Kundalini, Hatha, Restorative, Prenatal</p></div>
                <div className={`choice_container ${isChoiceClicked ? 'checkmark': 'choice_container'}`} onChange={this.handleChoice}><h5>Fitness</h5><p className="activities">Strength, Barre, Pilates, HIIT, Core, Stretching</p></div>
                <div  className={`choice_container ${isChoiceClicked ? 'checkmark': 'choice_container'}`} onChange={this.handleChoice}><h5>Mindfullness</h5><p className="activities">Meditation, Breathwork, Sound Bath, Yoga Nidra</p></div>
                <div className={`choice_container ${isChoiceClicked ? 'checkmark': 'choice_container'}`} onChange={this.handleChoice}><h5>Skills</h5><p className="activities">Handstands, Arm Balances, Flexibility, Mobility</p></div>
                </div>
                <div className="next"><button className="next_question">next question</button></div>
            </div>
    </div>
</div>
    }
    
    }

    export default Questions; ```

.choice_container {
  margin: 0 auto;
  width: 250px;
  padding: 1rem;
  border: solid 0.5px black;
  position: relative;
}

.choice_container .checkmark {
  display: hidden;
  position: absolute;
  border: solid 2px black;
  right: -8px;
  top: -8px;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background-color: #000;
  color: #fff;
  content: "✓";
}```

1 个答案:

答案 0 :(得分:1)

<块引用>

即使当我检查开发工具时,'checkmark' 是 className 但 onClick 没有任何变化

您激活的功能应该是onClick而不是onChange

通常 onChange 可用于 <input><select>。但是,如果您使用的是 div,则使用 onChange 似乎是一个问题。

<div className={`choice_container ${isChoiceClicked ? 'checkmark': 'null'}`} onClick={this.handleChoice}><h5>Yoga</h5><p className="activities">Vinyasa, Ashtanga, Kundalini, Hatha, Restorative, Prenatal</p></div>

此外,我猜你想从 this.state 解构。因此,您可以执行以下操作。

 const isChoiceClicked = this.state;

 const { isChoiceClicked } = this.state;