React评论添加和删除 React实现评论的添加和删除

时间:2021-03-15 qqz_2016 人气:0

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一、效果图

二、需求描述

1. 手动输入用户名和评论内容，点击提交；输入内容被追加到右侧评论列表；

2. 点击评论列表的“删除”按钮，弹框提示确定删除用户“xx”；

3. 点击“确定”，“xx”用户发表的评论被删除；

4. 所有评论均被删除时，显示“暂无评论，点击添加评论！！！”

三、代码实现

App.js

import React from 'react';
import './App.css';
import CommentAdd from '../src/components/CommentAdd'
import CommentList from '../src/components/CommentList'
import PropTypes from 'prop-types'
import "../src/assets/css/bootstrap.css"
 
class App extends React.Component {
 // 给组件对象指定state属性
 // 初始化状态
 state = {
 comments: [
  {username: "Tom", content: "React太容易了"},
  {username: "Jack", content: "React太难了"}
 ]
 }
 
 static propTypes = {
 comments: PropTypes.array.isRequired,
 addComment: PropTypes.func.isRequired,
 deleteComment: PropTypes.func.isRequired
 }
 
 addComment = (comment) => {
 // 将添加的评论追加到评论list上
 const {comments} = this.state
 comments.unshift(comment)
 // 更新状态
 this.setState({comments})
 }
 deleteComment = (index) => {
 const {comments} = this.state
 comments.splice(index, 1)
 this.setState({comments})
 }
 
 render() {
 const {comments} = this.state
 return (
  <div>
  <header className="site-header jumbotron">
   <div className="container">
   <div className="row">
    <div className="col-xs-12">
    <h2>评论管理列表</h2>
    </div>
   </div>
   </div>
  </header>
  <div className="container">
   <CommentAdd addComment={this.addComment}/>
   <CommentList comments={comments} deleteComment={this.deleteComment}/>
  </div>
  </div>
 );
 }
}
 
export default App;

CommentAdd.js

import React, {Component} from 'react';
import PropTypes from 'prop-types'
import "../assets/css/bootstrap.css"
 
class CommentAdd extends Component {
 
 state = {
 username: "",
 content: ""
 }
 
 static propTypes = {
 addComment: PropTypes.func.isRequired
 }
 handleNameChange = (event) => {
 const username = event.target.value
 this.setState({username});
 }
 handleContentChange = (event) => {
 const content = event.target.value
 this.setState({content});
 }
 handleSubmit = () => {
 const comment = this.state
 this.props.addComment(comment)
 // 清楚输入数据
 this.setState({
  username: "",
  content: ""
 });
 }
 
 render() {
 const {username, content} = this.props
 return (
  <div className="col-md-4">
  <form className="form-horizontal">
   <div className="form-group">
   <label>用户名：</label>
   <input type="text" className="form-control" placeholder="请输入用户名" value={username}
    onChange={this.handleNameChange}/><br/>
   </div>
   <div className="form-group">
   <label>评论内容：</label>
   <textarea className="form-control" rows="6" placeholder="请输入评论内容"
     value={content} onChange={this.handleContentChange}>
   </textarea>
   </div>
   <div className="form-group">
   <div className="col-sm-offset-2 col-sm-10">
    <button type="button" className="btn btn-default pull-right"
     onClick={this.handleSubmit}>提交
    </button>
   </div>
   </div>
  </form>
  </div>
 );
 }
}
 
export default CommentAdd;

CommentList.js

import React, {Component} from 'react';
import CommentItem from "./CommentItem";
import PropTypes from 'prop-types'
import "../assets/css/comment_list.css"
 
class CommentList extends Component {
 
 static propTypes = {
 comments: PropTypes.array.isRequired,
 deleteComment: PropTypes.func.isRequired
 }
 
 render() {
 const {comments, deleteComment} = this.props
 const display = comments.length === 0 ? "block" : "none"
 return (
 
  <div className="col-md-8">
  <h4>评论回复：</h4>
  <h5 style={{display}}>暂无评论，点击添加评论！！！</h5>
  <ul>
   {
   comments.map((comment, index) => <li key={index}><CommentItem comments={comment} index={index}
           deleteComment={deleteComment}/>
   </li>)
   }
  </ul>
  </div>
 );
 }
}
 
export default CommentList;

CommentItem.js

import React, {Component} from 'react';
import PropTypes from 'prop-types'
import "../assets/css/comment_item.css"
 
class CommentItem extends Component {
 static propTypes = {
 comments: PropTypes.array.isRequired,
 deleteComment: PropTypes.func.isRequired,
 index: PropTypes.number.isRequired
 }
 
 handleDeleteComment = () => {
 const {comments, deleteComment, index} = this.props
 if (window.confirm(`确定删除${comments.username}嘛？`)) {
  deleteComment(index)
 }
 }
 
 render() {
 const {comments} = this.props
 return (
  <div className="list-group-item">
  <div className="handle">
   <a href="javascript:;" rel="external nofollow" onClick={this.handleDeleteComment}>删除</a>
  </div>
  <p className="user"><span>{comments.username}</span><span>说：</span></p>
  <p className="centence">{comments.content}</p>
  </div>
 );
 }
}
 
export default CommentItem;

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