How to toggle class for the only one element on click in react

问题

I am trying to make a flipped set of cards in React. You can see my code below. When I click on the card, they all flipped, but my goal is to flip only those that i clicked on. How can I do this?

This is my card component:

import React from 'react';

export default class Card extends React.Component {
    render() {
        let className = this.props.condition ? 'card-component flipped' : 'card-component';
        return (
            <div onClick={this.props.handleClick} className={className}>
                <div className="front">
                    <img src={this.props.image} alt="card"/>
                </div>
                <div className="back">
                </div>
            </div>);
    }
}

Here is my Deck component:

import React from 'react';
import Card from './Card.js';

const cardlist = require('../cardlist').cardlist;

export default class Deck extends React.Component{
    constructor(props) {
        super(props);
        this.state = {flipped: false};
    }
    handleClick() {
        this.setState({flipped: !this.state.flipped});
    }
    render() {
        const list = this.props.cards.map((card, index) => {
            return <Card
                         key={index}
                         handleClick={this.handleClick.bind(this)}
                         condition={this.state.flipped}
                         image={cardlist[card].path}
                    />});
        return(
            <ul>
                {list}
            </ul>)
    }
};

Thank you!

回答1:

You can make use of indexes.

export default class Deck extends React.Component{
    constructor(props) {
        super(props);

        //flipped true nonflipped false
        this.state = {
         flipStatus : props.cards.map((element) => false)
        }
    handleClick(index) {

        const newflipStatus = [...this.state.flipStatus]
        newflipStatus[index] = !this.state.flipStatus[index]
        this.setState({flipStatus: newflipStatus);
    }
    render() {
        const list = this.props.cards.map((card, index) => {
            return <Card
                         key={index}
                         handleClick={this.handleClick.bind(this)}
                         condition={this.state.flipped}
                         index={index}
                         image={cardlist[card].path}
                         flipped=this.state.flipStatus[index]

                    />});
        return(
            <ul>
                {list}
            </ul>)
    }
};

here is your card component

export default class Card extends React.Component {
    render() {
        let className = this.props.condition ? 'card-component flipped' : 'card-component';
        return (
            <div onClick={() => this.props.handleClick(this.props.index)} className={className}>
                {!flipped && <div className="front">
                    <img src={this.props.image} alt="card"/>
                </div>}
                {flipped && <div className="back">
                </div>}
            </div>);
    }
}

回答2:

in the handleClick function you are setting the "flipped" state variable for the whole deck not for a single card, that's why the whole deck changes together. the solution would be simple to have a state for each card to designate if it's flipped or not, rather than making the variable on the parent level

来源：https://stackoverflow.com/questions/48289315/how-to-toggle-class-for-the-only-one-element-on-click-in-react

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javascript

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reactjs

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