React实现评论的添加和删除

本文实例为大家分享了Android九宫格图片展示的具体代码，供大家参考，具体内容如下

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;

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。

原文链接：https://blog.csdn.net/zqq_2016/article/details/109145553