一、react基本应用

一、helloworld(可直接用浏览器打开文件即可)

cdn:bootcdn有各种js 的cdn; 一般提供开发版（js未压缩）和生产版（js压缩过了）

需要引入3个js

核心库：<script src="./node_modules/react/umd/react.development.js"></script>

操作dom的扩展库：<script src="./node_modules/react-dom/umd/react-dom.development.js"></script>

解析jsx语法代码转为js语法代码的库：<script src="./dist/bundle.js"></script>

helloworld代码：

 1 <!DOCTYPE html>
 2 <html>
 3   <head>
 4     <meta charset="UTF-8" />
 5     <title>Add React in One Minute</title>
 6   </head>
 7   <body>
 8 
 9    
10     <!-- Load React. -->
11     <!-- Note: when deploying, replace "development.js" with "production.min.js". -->
12     <script src="https://unpkg.com/react@18/umd/react.development.js" crossorigin></script>
13     <script src="https://unpkg.com/react-dom@18/umd/react-dom.development.js" crossorigin></script>
14     <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>
15     <div id="example"></div> 
16     <script type="text/babel">
17       //1.创建虚拟DOM元素对象
18       var vDOM=<h1> HELLO WORLD</h1>
19   
20       //2.将虚拟DOM渲染到真是的ROM容器中
21       ReactDOM.render(vDOM,document.getElementById("example"));
22     </script>
23 
24 
25   </body>
26 </html>

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页面显示 HELLO WORLD

两种方式，实现react hello world；

jsx写法：const vDom2 = <h3 id={id.toLocaleUpperCase()}>{msg.toLocaleLowerCase()}</h3>;

"<"代表标签开始
“{”代表js代码开始

 1 <!DOCTYPE html>
 2 <html>
 3   <head>
 4     <meta charset="UTF-8" />
 5     <title>Add React in One Minute</title>
 6   </head>
 7   <body>
 8 
 9     <h2>Add React in One Minute</h2>
10   
11 <div id="test"></div>
12 <div id="test2"></div>
13     <!-- Load React. -->
14     <!-- Note: when deploying, replace "development.js" with "production.min.js". -->
15     <script src="https://unpkg.com/react@18/umd/react.development.js" crossorigin></script>
16     <script src="https://unpkg.com/react-dom@18/umd/react-dom.development.js" crossorigin></script>
17     <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>
18 
19 
20     <script>
21       const msg = "AAAA BBBB  VVV   DD!";
22       const id = "xsdfsdf"
23      //1.创建虚拟DOM ;参数：标签名，标签属性（键值对）；标签内容
24      const vDom1 = React.createElement("h2",{id:id.toLowerCase()},msg.toUpperCase());
25      //2.渲染虚拟DOM 参数：虚拟对象 ，DOM容器
26      ReactDOM.render(vDom1,document.getElementById("test"));
27     </script>
28 
29 <script type="text/babel">
30  //1.创建虚拟DOM 
31  const vDom2 = <h3 id={id.toLocaleUpperCase()}>{msg.toLocaleLowerCase()}</h3>;
32  //2.渲染虚拟DOM 参数：虚拟对象 ，DOM容器
33  ReactDOM.render(vDom2,document.getElementById("test2"));
34 </script>
35   </body>
36 </html>

数组用列表形式显示：

 1 <!DOCTYPE html>
 2 <html>
 3   <head>
 4     <meta charset="UTF-8" />
 5     <title>Add React in One Minute</title>
 6   </head>
 7   <body>  
 8 <div id="example"></div>
 9     <!-- Load React. -->
10     <!-- Note: when deploying, replace "development.js" with "production.min.js". -->
11     <script src="https://unpkg.com/react@18/umd/react.development.js" crossorigin></script>
12     <script src="https://unpkg.com/react-dom@18/umd/react-dom.development.js" crossorigin></script>
13     <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>
14 
15    
16 
17 <script type="text/babel">
18     //需求：数组用列表显示
19     //问题：如何将一个数据的数字转换为一个标签的数组
20     //利用数组的map函数
21      const names=["jqyer","react","vue"];
22  //1.创建虚拟DOM 
23  const vDom2 = <ul>{
24     names.map((name,index)=><li key={index}>{name}</li>)
25 }</ul>
26  //2.渲染虚拟DOM 参数：虚拟对象 ，DOM容器
27  ReactDOM.render(vDom2,document.getElementById("example"));
28 </script>
29   </body>
30 </html>

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组件编程的基本定义和使用：

简单组件（组件无状态）和复杂组件（组件有状态）

 1 <!DOCTYPE html>
 2 <html>
 3   <head>
 4     <meta charset="UTF-8" />
 5     <title>Add React in One Minute</title>
 6   </head>
 7   <body>  
 8 <div id="example"></div>
 9 <div id="example2"></div>
10     <!-- Load React. -->
11     <!-- Note: when deploying, replace "development.js" with "production.min.js". -->
12     <script src="https://unpkg.com/react@18/umd/react.development.js" crossorigin></script>
13     <script src="https://unpkg.com/react-dom@18/umd/react-dom.development.js" crossorigin></script>
14     <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>
15 
16    
17 
18 <script type="text/babel">
19  
20  //1.定义组件 组件名称大写
21  //方式1：工厂函数组件（简单组件） 必须要return;
22  function MyComponent(){
23 return <h2>工厂函数组件（简单组件）</h2>
24  }
25  //方式2：ES6类组件(复杂组件)
26  class MyComponent2 extends React.Component{
27     render(){
28         return <h2>ES6类组件(复杂组件)</h2>
29     }
30  }
31  //2.渲染组件,容器DOM
32  ReactDOM.render(<MyComponent/>,document.getElementById('example'));
33  ReactDOM.render(<MyComponent2/>,document.getElementById('example2'));
34 </script>
35   </body>
36 </html>

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简单组件实现结合props的相关说明

 1 <!DOCTYPE html>
 2 <html>
 3   <head>
 4     <meta charset="UTF-8" />
 5     <title>Add React in One Minute</title>
 6   </head>
 7   <body>  
 8 <div id="like"></div>
 9 <div id="like2"></div>
10     <!-- Load React. -->
11     <!-- Note: when deploying, replace "development.js" with "production.min.js". -->
12     <script src="https://unpkg.com/react@18/umd/react.development.js" crossorigin></script>
13     <script src="https://unpkg.com/react-dom@18/umd/react-dom.development.js" crossorigin></script>
14     <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>
15     <script src="/my-app/node_modules/prop-types/prop-types.min.js"></script>
16 
17    
18 
19 <script type="text/babel">
20  
21  //1.定义组件 组件名称大写
22  //方式1：
23  function PersonInfo(props){
24  return <ul><li>姓名：{props.name}</li><li>年龄：{props.age}</li><li>性别：{props.sex}</li></ul>
25  }
26 
27  //指定属性默认值
28  PersonInfo.defaultProps={
29     sex:"男",
30     age:18
31  }
32  //对props中的属性今昔类型限制和必要性限制
33 //  PersonInfo.propTypes = {
34 //   name: PropTypes.string
35 // }
36  //2.渲染组件标签,容器DOM
37  const p1={
38     name:"TOM",
39     age:12,
40     sex:"女"
41  }
42 
43  const p2={
44     name:"TOM"
45  }
46  
47  //传值也可使用...p1
48  //...的作用：1.打包，2.解包
49  //1.打包 function fn(...as){}  fn(1,2,3) 参数放到数组as中
50  //2.解包 const arr1=[1,2,3]  const arr2=[6,...arr1,9]  即[6,1,2,3,9]
51  
52 //  ReactDOM.render(<PersonInfo name={p1.name} age={p1.age} sex={p1.sex}/>,document.getElementById('like'));
53 ReactDOM.render(<PersonInfo{...p1}/>,document.getElementById('like'));
54  ReactDOM.render(<PersonInfo name={p2.name}/>,document.getElementById('like2'));
55 
56 </script>
57   </body>
58 </html>

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复杂组件的相关说明：state的状态和将新增的方法强制绑定为组件对象；

state：初始化状态，读取状态，更新状态；

注意：

return 只能有一个根标签；
将新增方法中的this强制绑定为组件对象，需要在构造器中加入t额外加入his.handleClick = this.handleClick.bind(this)；如果不想在构造器中加入绑定，那么方法可以直接用箭头函数；否则一定要在构造器中绑定对象；

 1 <!DOCTYPE html>
 2 <html>
 3   <head>
 4     <meta charset="UTF-8" />
 5     <title>Add React in One Minute</title>
 6   </head>
 7   <body>  
 8 <div id="like"></div>
 9     <!-- Load React. -->
10     <!-- Note: when deploying, replace "development.js" with "production.min.js". -->
11     <script src="https://unpkg.com/react@18/umd/react.development.js" crossorigin></script>
12     <script src="https://unpkg.com/react-dom@18/umd/react-dom.development.js" crossorigin></script>
13     <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>
14 
15    
16 
17 <script type="text/babel">
18  
19  //1.定义组件 组件名称大写
20  //方式2：ES6类组件(复杂组件)
21  class Like extends React.Component{
22     constructor(prop){
23         super(prop)
24         //初始化状态
25         this.state={
26             isOpen:false
27         }
28         //将新增方法中的this强制绑定为组件对象
29         this.handleClick = this.handleClick.bind(this)
30     }
31     //新添加方法：内部的this默认是undefined 不是组件对象
32     handleClick(){
33         const isOpen = !this.state.isOpen
34         //更新状态
35         //this.setState({isOpen:isOpen}) 等同于this.setState({isOpen}) !
36         this.setState({isOpen}) 
37     }
38     //重写组件方法
39     render(){
40         console.log(this);//组件实例对象
41         //读取状态
42         const {isOpen} = this.state
43         return <h2 onClick={this.handleClick}>{isOpen?"关":"开"}</h2>
44     }
45  }
46  //2.渲染组件标签,容器DOM
47  ReactDOM.render(<Like/>,document.getElementById('like'));
48 </script>
49   </body>
50 </html>

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ref、事件event获取元素的值

 1 <!DOCTYPE html>
 2 <html>
 3   <head>
 4     <meta charset="UTF-8" />
 5     <title>Add React in One Minute</title>
 6   </head>
 7   <body>  
 8 <div id="example"></div>
 9     <!-- Load React. -->
10     <!-- Note: when deploying, replace "development.js" with "production.min.js". -->
11     <script src="https://unpkg.com/react@18/umd/react.development.js" crossorigin></script>
12     <script src="https://unpkg.com/react-dom@18/umd/react-dom.development.js" crossorigin></script>
13     <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>
14     <script src="/my-app/node_modules/prop-types/prop-types.min.js"></script>
15 
16    
17 
18 <script type="text/babel">
19  
20  //1.定义组件 组件名称大写
21 class LearnRef extends React.Component{
22   constructor(props){
23     super(props);
24     this.showInput = this.showInput.bind(this);
25     this.handleBlur = this.handleBlur.bind(this);
26   }
27   showInput(){
28     alert("方式二："+this.elementKey.value);
29   }
30   handleBlur(event){
31     alert(event.target.value);
32   }
33   // ref={input=>this.elementKey=input} input表示当前input元素  elementKey 表示对象的键值对的键值
34   render(){
35     return <div>
36       <input type="text" ref={input=>this.elementKey=input}/><br/>
37       <input type="text" placeholder="失去焦点提示内容" onBlur={this.handleBlur}/><br/>
38       <button onClick={this.showInput}>输入提示</button>
39       </div>
40   }
41 }
42 //2.渲染组件
43  ReactDOM.render(<LearnRef/>,document.getElementById('example'));
44 
45 </script>
46   </body>
47 </html>

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组件化编程

流程：

1.拆分组件

2.实现静态组件（只有静态页面，没有动态数据和交互）

3.实现动态组件：1）。实现初始化数据动态显示；2）.实现交互功能：

demo实现功能如下：

  1 <!DOCTYPE html>
  2 <html>
  3 
  4 <head>
  5   <meta charset="UTF-8" />
  6   <title>Add React in One Minute</title>
  7 
  8 </head>
  9 
 10 <body>
 11   <div id="example"></div>
 12   <!-- Load React. -->
 13   <!-- Note: when deploying, replace "development.js" with "production.min.js". -->
 14   <script src="https://unpkg.com/react@18/umd/react.development.js" crossorigin></script>
 15   <script src="https://unpkg.com/react-dom@18/umd/react-dom.development.js" crossorigin></script>
 16   <script src="https://cdn.bootcdn.net/ajax/libs/prop-types/15.8.1/prop-types.min.js"></script>
 17   <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>
 18 
 19 
 20 
 21 <!-- <script src="learn.js"></script> -->
 22 <script type="text/babel">
 23     //1.定义组件 组件名称大写
 24     class App extends React.Component {
 25       constructor(props) {
 26         super(props);
 27         this.state={
 28           todos:["eat","sleep","coding"]
 29         }
 30         this.addTodo = this.addTodo.bind(this);
 31       }
 32 
 33       addTodo(todo){
 34        // this.state.todos.unshift(todo); 不可以这么写
 35        const {todos}=this.state;
 36        todos.unshift(todo);
 37        //跟新状态
 38        this.setState({todos});
 39 
 40       }
 41       render() {
 42 
 43         return (
 44           <div>
 45             <h1>simple todo list</h1>
 46           <Add count={this.state.todos.length} addTodo={this.addTodo}/>
 47           <List todos={this.state.todos}/>
 48             </div>
 49 
 50         )
 51       }
 52     }
 53 
 54     class Add extends React.Component {
 55       constructor(props) {
 56         super(props);
 57        this.add=this.add.bind(this);
 58       }
 59       add(){
 60         const todo = this.todoItem.value.trim();
 61         if(!todo){
 62           return;
 63         }
 64         this.props.addTodo(todo);
 65       }
 66       render(){
 67         return (
 68           <div>
 69           <input type="text" ref={input=>this.todoItem=input}/><button onClick={this.add}>添加#{this.props.count+1}</button>  
 70           </div>
 71         )
 72       }
 73     }
 74     class List extends React.Component {
 75       constructor(props) {
 76         super(props);
 77       }
 78       render(){
 79         return (
 80           <ul>
 81           {this.props.todos.map((todo,index)=><li key={index}>{todo}</li>)}
 82           </ul>
 83         )
 84       }
 85     }
 86     //参数设置限制
 87     List.propTypes = {
 88       todos: PropTypes.array.isRequired
 89 };
 90 Add.propTypes = {
 91       count: PropTypes.number.isRequired,
 92       addTodo:PropTypes.func.isRequired
 93 };
 94     //2.渲染组件
 95     ReactDOM.render(<App />, document.getElementById('example'));
 96 
 97   </script> 
 98 </body>
 99 
100 </html>

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关于限制项的另外一种写法：必须要写在组件内。表示该组件类的限制

static propTypes = {

todos: PropTypes.array.isRequired
};

  1 <!DOCTYPE html>
  2 <html>
  3 
  4 <head>
  5   <meta charset="UTF-8" />
  6   <title>Add React in One Minute</title>
  7 
  8 </head>
  9 
 10 <body>
 11   <div id="example"></div>
 12   <!-- Load React. -->
 13   <!-- Note: when deploying, replace "development.js" with "production.min.js". -->
 14   <script src="https://unpkg.com/react@18/umd/react.development.js" crossorigin></script>
 15   <script src="https://unpkg.com/react-dom@18/umd/react-dom.development.js" crossorigin></script>
 16   <script src="https://cdn.bootcdn.net/ajax/libs/prop-types/15.8.1/prop-types.min.js"></script>
 17   <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>
 18 
 19 
 20 
 21 <!-- <script src="learn.js"></script> -->
 22 <script type="text/babel">
 23     //1.定义组件 组件名称大写
 24     class App extends React.Component {
 25       constructor(props) {
 26         super(props);
 27         this.state={
 28           todos:["eat","sleep","coding"]
 29         }
 30         this.addTodo = this.addTodo.bind(this);
 31       }
 32 
 33       addTodo(todo){
 34        // this.state.todos.unshift(todo); 不可以这么写
 35        const {todos}=this.state;
 36        todos.unshift(todo);
 37        //跟新状态
 38        this.setState({todos});
 39 
 40       }
 41       render() {
 42 
 43         return (
 44           <div>
 45             <h1>simple todo list</h1>
 46           <Add count={this.state.todos.length} addTodo={this.addTodo}/>
 47           <List todos={this.state.todos}/>
 48             </div>
 49 
 50         )
 51       }
 52     }
 53 
 54     class Add extends React.Component {
 55       constructor(props) {
 56         super(props);
 57        this.add=this.add.bind(this);
 58       }
 59       add(){
 60         const todo = this.todoItem.value.trim();
 61         if(!todo){
 62           return;
 63         }
 64         this.props.addTodo(todo);
 65       }
 66       render(){
 67         return (
 68           <div>
 69           <input type="text" ref={input=>this.todoItem=input}/><button onClick={this.add}>添加#{this.props.count+1}</button>
 70           </div>
 71         )
 72       }
 73     }
 74     class List extends React.Component {
 75     //参数设置限制的另外一种写法
 76     static propTypes = {
 77       todos: PropTypes.array.isRequired
 78 };
 79       constructor(props) {
 80         super(props);
 81       }
 82       render(){
 83         return (
 84           <ul>
 85           {this.props.todos.map((todo,index)=><li key={index}>{todo}</li>)}
 86           </ul>
 87         )
 88       }
 89     }
 90     //参数设置限制
 91 Add.propTypes = {
 92       count: PropTypes.number.isRequired,
 93       addTodo:PropTypes.func.isRequired
 94 };
 95     //2.渲染组件
 96     ReactDOM.render(<App />, document.getElementById('example'));
 97 
 98   </script>
 99 </body>
100 
101 </html>

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获取表单数据：

获取组件值的方式有两种：1.受控组件方式（表单输入数据能自动收集成状态：可以理解为onChange方式）；2.非受控组件方式（r需要时，才手动读取输入框中的值，可以理解为ef方式）

 1 <!DOCTYPE html>
 2 <html>
 3 
 4 <head>
 5   <meta charset="UTF-8" />
 6   <title>Add React in One Minute</title>
 7 
 8 </head>
 9 
10 <body>
11   <div id="example"></div>
12   <!-- Load React. -->
13   <!-- Note: when deploying, replace "development.js" with "production.min.js". -->
14   <script src="https://unpkg.com/react@18/umd/react.development.js" crossorigin></script>
15   <script src="https://unpkg.com/react-dom@18/umd/react-dom.development.js" crossorigin></script>
16   <script src="https://cdn.bootcdn.net/ajax/libs/prop-types/15.8.1/prop-types.min.js"></script>
17   <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>
18 
19 
20 
21 <!-- <script src="learn.js"></script> -->
22 <script type="text/babel">
23     //1.定义组件 组件名称大写
24     class GetFormInfo extends React.Component {
25       constructor(props) {
26         super(props);
27         this.handleChange=this.handleChange.bind(this);
28         this.handleSubmit = this.handleSubmit.bind(this);
29         this.state={
30           pwd:''
31         }
32       }
33 
34       handleChange(event){
35         const pwd = event.target.value;
36         //更新状态
37         this.setState({pwd});
38       }
39       handleSubmit(){
40         const name = this.name.value;
41         const {pwd}=this.state;
42         alert("当前填写的表单信息为：用户名："+name+",密码："+pwd);
43       }
44       render() {
45 
46         return (
47           <form onSubmit={this.handleSubmit}>
48            用户名：<input type="text" ref={input=>this.name = input}/>
49            密码：<input type="password"  onChange={this.handleChange} value={this.state.pwd}/>
50             <input type="submit" value="显示表单信息"/>
51             </form>
52 
53         )
54       }
55     }
56     //2.渲染组件
57     ReactDOM.render(<GetFormInfo />, document.getElementById('example'));
58 
59   </script> 
60 </body>
61 
62 </html>

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组件的生命周期

1. 组件的三个生命周期状态:

Mount：插入真实 DOM
Update：被重新渲染
Unmount：被移出真实 DOM

2. 生命周期流程:

* 第一次初始化显示: ReactDOM.render(<Xxx/>, containDom)

constructor()
componentWillMount() : 将要插入回调
render() : 用于插入虚拟DOM回调
componentDidMount() : 已经插入回调

* 每次更新state: this.setState({})

componentWillReceiveProps(): 接收父组件新的属性
componentWillUpdate() : 将要更新回调
render() : 更新(重新渲染)
componentDidUpdate() : 已经更新回调

* 删除组件: ReactDOM.unmountComponentAtNode(div): 移除组件

componentWillUnmount() : 组件将要被移除回调

3. 常用的方法

render(): 必须重写, 返回一个自定义的虚拟DOM
constructor(): 初始化状态, 绑定this(可以箭头函数代替)
componentDidMount() : 只执行一次, 已经在dom树中, 适合启动/设置一些监听！

demo 效果图：

 1 <!DOCTYPE html>
 2 <html>
 3 
 4 <head>
 5   <meta charset="UTF-8" />
 6   <title>Add React in One Minute</title>
 7 
 8 </head>
 9 
10 <body>
11   <div id="example"></div>
12   <!-- Load React. -->
13   <!-- Note: when deploying, replace "development.js" with "production.min.js". -->
14   <script src="https://unpkg.com/react@18/umd/react.development.js" crossorigin></script>
15   <script src="https://unpkg.com/react-dom@18/umd/react-dom.development.js" crossorigin></script>
16   <script src="https://cdn.bootcdn.net/ajax/libs/prop-types/15.8.1/prop-types.min.js"></script>
17   <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>
18 
19 
20 
21 <!-- <script src="learn.js"></script> -->
22 <script type="text/babel">
23     //1.定义组件 组件名称大写
24     class Life extends React.Component {
25       constructor(props) {
26         super(props);
27        
28         this.state={
29           opcity:1
30         }
31         this.handleClick = this.handleClick.bind(this);
32       }
33 
34       componentDidMount(){
35         this.intervalId =setInterval(function(){
36           let {opcity}= this.state;
37           opcity -= 0.1;
38           if(opcity<0){
39             opcity = 1;
40           }
41           this.setState({opcity})
42         }.bind(this),500)
43       }
44       componentWillUnmount(){
45         clearInterval(this.intervalId);
46       }
47       handleClick(){
48           ReactDOM.unmountComponentAtNode(document.getElementById('example'));
49       }
50       render() {
51         const {opcity}=this.state
52         return (
53          <div>
54           <h2 style={{opacity:opcity}}> react 太难了</h2>
55           <button onClick={this.handleClick}>不活了</button>
56           </div>
57 
58         )
59       }
60     }
61     //2.渲染组件
62     ReactDOM.render(<Life />, document.getElementById('example'));
63 
64   </script> 
65 </body>
66 
67 </html>

View Code

组件模板：

一般写组件可以在这个模板里面写：

 1 import React, { Component } from 'react';
 2 export default class defalutApp extends Component {
 3   constructor(props) {
 4     super(props);
 5     this.state = {
 6     }
 7   }
 8   render() {
 9 
10     return (
11       <div>
12       </div>
13 
14     )
15   }
16 }

View Code

axios 请求

 1 <!DOCTYPE html>
 2 <html>
 3 <head>
 4   <meta charset="UTF-8">
 5   <title>11_ajax</title>
 6 </head>
 7 <body>
 8 <div id="example"></div>
 9 
10 <script type="text/javascript" src="../js/react.development.js"></script>
11 <script type="text/javascript" src="../js/react-dom.development.js"></script>
12 <script type="text/javascript" src="../js/babel.min.js"></script>
13 <script src="https://cdn.bootcdn.net/ajax/libs/axios/0.27.2/axios.js"></script>
14 <script type="text/babel">
15   /*
16   需求:
17     1. 界面效果如下
18     2. 根据指定的关键字在github上搜索匹配的最受关注的库
19     3. 显示库名, 点击链接查看库
20     4. 测试接口: https://api.github.com/search/repositories?q=r&sort=stars
21   */
22 class AxiosComponent extends React.Component{
23   state={
24     repoName:"",
25     repoUrl:""
26   }
27   componentDidMount(){
28     const url = "https://api.github.com/search/repositories?q=r&sort=stars";
29     axios.get(url).then(response=>{
30       console.log(response.data);
31       const result = response.data
32       this.setState({
33         repoName:result.items[0].name,repoUrl:result.items[0].html_url
34       })
35     })
36   }
37   render(){
38     const {repoName,repoUrl} = this.state;
39     if(!repoName){
40       return(
41       <h2>Loading...</h2>
42     )
43     }else{
44       return <h2>最受欢迎的组件是<a href={repoUrl}>{repoName}</a></h2>
45     }
46     return(
47       <div></div>
48     )
49   }
50 }
51 ReactDOM.render(<AxiosComponent/>,document.getElementById("example"))
52 </script>
53 </body>
54 </html>

View Code

组件之间的参数传递：

1.props传递；以上例子都是使用props传递，不再赘述

2.使用消息订阅（subscribe）-发布（publish)机制；

在当前项目安装pubsub-js：npm install --save pubsub-js
github地址：https://github.com/mroderick/PubSubJS
发布消息：PubSub.publish('MY TOPIC', 'hello world!');
订阅消息：var token = PubSub.subscribe('MY TOPIC', mySubscriber);

订阅消息的说明：

var token = PubSub.subscribe('MY TOPIC', mySubscriber);

var mySubscriber = function (msg, data) { console.log(msg, data); };

订阅位置：一般是在componentDidMount() 里面设置订阅；

3.redux

react-router:

说明react v5到v6:

Switch 重命名为 Routes
Route 的新特性变更 ,component/render被element替代
react-router-dom 6版本移除了 Redirect，用 Navigate 代替

创建:npx create-react-app react-app

1.下载 npm install --save react-router-dom

2.helloword代码：

index.html:

 1 <!DOCTYPE html>
 2 <html lang="en">
 3   <head>
 4     <meta charset="utf-8" />
 5     <link rel="icon" href="%PUBLIC_URL%/favicon.ico" />
 6     <meta name="viewport" content="width=device-width, initial-scale=1" />
 7     <meta name="theme-color" content="#000000" />
 8     <meta
 9       name="description"
10       content="Web site created using create-react-app"
11     />
12     <link rel="apple-touch-icon" href="%PUBLIC_URL%/logo192.png" />
13     <link rel="stylesheet" href="css/bootstrap.css" />
14     <title>React App</title>
15   </head>
16   <body>
17     <noscript>You need to enable JavaScript to run this app.</noscript>
18     <div id="root"></div>
19   </body>
20 </html>

View Code

app.jsx:

 1 import React, { Component } from 'react';
 2 import {Route, Switch, Redirect,NavLink} from 'react-router-dom'
 3 import Home from '../views/home.jsx';
 4 import About from '../views/about.jsx';
 5 export default class App extends Component {
 6   constructor(props) {
 7     super(props);
 8     this.state = {
 9     }
10   }
11   render() {
12     return (
13       <div>
14         <div className="row">
15           <div className="col-xs-offset-2 col-xs-8">
16             <div className="page-header">
17               <h2>React Router Demo</h2>
18             </div>
19           </div>
20         </div>
21 
22         <div className="row">
23           <div className="col-xs-2 col-xs-offset-2">
24             <div className="list-group">
25               {/*导航路由链接*/}
26               <NavLink className="list-group-item" activeClassName="activeClass" to='/about'>About</NavLink>
27               <NavLink className="list-group-item" activeClassName="activeClass" to='/home'>Home</NavLink>
28             </div>
29           </div>
30           <div className="col-xs-6">
31             <div className="panel">
32               <div className="panel-body">
33                 {/*可切换的路由组件*/}
34                 <Switch>
35                   <Route path='/about' component={About}/>
36                   <Route path='/home' component={Home}/>
37                     {/*可切换的路由组件 默认显示about*/}
38                   <Redirect to='/about'/>
39                 </Switch>
40               </div>
41             </div>
42           </div>
43         </div>
44       </div>
45     )
46   }
47 }

View Code

home.jsx:

 1 import React, { Component } from 'react';
 2 export default class Home extends Component {
 3   constructor(props) {
 4     super(props);
 5     this.state = {
 6     }
 7   }
 8   render() {
 9 
10     return (
11       <div>
12         HOME
13       </div>
14 
15     )
16   }
17 }

View Code

about.jsx:

 1 import React, { Component } from 'react';
 2 export default class About extends Component {
 3   constructor(props) {
 4     super(props);
 5     this.state = {
 6     }
 7   }
 8   render() {
 9 
10     return (
11       <div>
12         ABOUT
13       </div>
14 
15     )
16   }
17 }

View Code

index.css:

1 .activeClass {
2   color: red !important;
3 }

View Code

index.js:

 1 import React from 'react';
 2 import ReactDOM from 'react-dom/client';
 3 import APP from './component/app.jsx';
 4 import { BrowserRouter, HashRouter } from 'react-router-dom';
 5 import './index.css'
 6 const root = ReactDOM.createRoot(document.getElementById('root'));
 7 root.render(
 8 
 9   //需要用路由包裹整个应用 ,意思就是路由管理整个应用
10   <BrowserRouter>
11     <React.StrictMode>
12       <APP />
13     </React.StrictMode>
14   </BrowserRouter>
15 );
16 
17 // If you want to start measuring performance in your app, pass a function
18 // to log results (for example: reportWebVitals(console.log))
19 // or send to an analytics endpoint. Learn more: https://bit.ly/CRA-vitals

View Code

包装组件：

1 import React, { Component } from 'react';
2 import {NavLink} from 'react-router-dom';
3 export default function MyNavLink(props)  {
4     return <NavLink {...props} activeClassName="activeClass"/>
5 }

包装组件的使用：

 1 import React, { Component } from 'react';
 2 import {Route, Switch, Redirect,NavLink} from 'react-router-dom'
 3 import Home from '../views/home.jsx';
 4 import About from '../views/about.jsx';
 5 import MyNavLink from './myNavLink.jsx';
 6 export default class App extends Component {
 7   constructor(props) {
 8     super(props);
 9     this.state = {
10     }
11   }
12   render() {
13     return (
14       <div>
15         <div className="row">
16           <div className="col-xs-offset-2 col-xs-8">
17             <div className="page-header">
18               <h2>React Router Demo</h2>
19             </div>
20           </div>
21         </div>
22 
23         <div className="row">
24           <div className="col-xs-2 col-xs-offset-2">
25             <div className="list-group">
26               {/*导航路由链接*/}
27               <MyNavLink className="list-group-item"  to='/about'>About</MyNavLink>
28               <MyNavLink className="list-group-item" to='/home'>Home</MyNavLink>
29             </div>
30           </div>
31           <div className="col-xs-6">
32             <div className="panel">
33               <div className="panel-body">
34                 {/*可切换的路由组件*/}
35                 <Switch>
36                   <Route path='/about' component={About}/>
37                   <Route path='/home' component={Home}/>
38                     {/*可切换的路由组件 默认显示about*/}
39                   <Redirect to='/about'/>
40                 </Switch>
41               </div>
42             </div>
43           </div>
44         </div>
45       </div>
46     )
47   }
48 }

View Code

嵌套路由：

/home 那么/home/news 就是嵌套路由；

demo修改：

效果：

步骤一：在views中添加路由组件news 和message

news:

 1 import React, { Component } from 'react';
 2 export default class News extends Component {
 3   constructor(props) {
 4     super(props);
 5     this.state = {
 6       newsArray:[
 7         "news001",
 8         "news002",
 9         "news003"
10       ]
11     }
12   }
13   render() {
14 
15     return (
16      <ul>{this.state.newsArray.map((item,index)=><li key={index}>{item}</li>)}</ul>
17     )
18     }
19 }

View Code

message:

 1 import React, { Component } from 'react';
 2 export default class Message extends Component {
 3   constructor(props) {
 4     super(props);
 5     this.state = {
 6       msgArray:[
 7       ]
 8     }
 9   }
10   componentDidMount(){
11     //模拟发送ajax请求异步获取数据
12     setTimeout(()=>{
13       const msgArray = [
14         {"id":1,"title":"msgArray001"},
15         {"id":2,"title":"msgArray0012"},
16         {"id":3,"title":"msgArray0013"}
17       ]
18       this.setState({msgArray})
19     },1000)
20   }
21   render() {
22 
23     return (
24      <ul>{this.state.msgArray.map((item,index)=>(<li key={index}><a href='???'>{item.title}</a></li>))}</ul>
25     )
26     }
27 }

View Code

步骤二：修改home.jsx:

 1 import React, { Component } from 'react';
 2 import MyNavLink from '../component/myNavLink';
 3 import {Route, Switch,Redirect} from 'react-router-dom';
 4 import News from './news.jsx';
 5 import Message from './message.jsx';
 6 export default class Home extends Component {
 7   constructor(props) {
 8     super(props);
 9     this.state = {
10     }
11   }
12   render() {
13 
14     return (
15       <div>
16         <h2>HOME ROUTE COMPONET </h2>
17         <div>
18           <ul className='nav nav-tabs'>
19             <li>
20               <MyNavLink to="/home/news">news</MyNavLink>
21             </li>
22             <li>
23               <MyNavLink to="/home/message">message</MyNavLink>
24             </li>
25           </ul>
26           <div>
27             <Switch>
28             <Route path="/home/news" component={News}/>
29             <Route path="/home/message" component={Message}/>
30             <Redirect to='/home/news'/>
31             </Switch>
32           </div>
33         </div>
34       </div>
35 
36     )
37   }
38 }

View Code

传参：

效果图：

添加一个message-detail:

 1 import React from 'react'
 2 
 3 const messageDetails = [
 4   {id: 1, title: 'Message001', content: '我爱你, 中国'},
 5   {id: 3, title: 'Message003', content: '我爱你, 老婆'},
 6   {id: 6, title: 'Message006', content: '我爱你, 孩子'},
 7 ]
 8 
 9 export default function MessageDetail(props) {
10 
11   const id = props.match.params.id
12   const md = messageDetails.find(md => md.id===id*1)
13   return (
14     <ul>
15       <li>ID:{id}</li>
16       <li>TITLE: 3333</li>
17       <li>CONTENT: 444</li>
18     </ul>
19   )
20 }

View Code

message.jsx，添加点击功能，动态显示详情

 1 import React from 'react'
 2 import {Link, Route} from 'react-router-dom'
 3 import MessageDetail from "./message-detail"
 4 
 5 export default class Message extends React.Component {
 6   state = {
 7     messages: []
 8   }
 9 
10   componentDidMount () {
11     // 模拟发送ajax请求
12     setTimeout(() => {
13       const data = [
14         {id: 1, title: 'Message001'},
15         {id: 3, title: 'Message003'},
16         {id: 6, title: 'Message006'},
17       ]
18       this.setState({
19         messages: data
20       })
21     }, 1000)
22   }
23 
24   ShowDetail = (id) => {
25     this.props.history.push(`/home/message/${id}`)
26   }
27 
28   ShowDetail2 = (id) => {
29     this.props.history.replace(`/home/message/${id}`)
30   }
31 
32   back = () => {
33     this.props.history.goBack()
34   }
35 
36   forward = () => {
37     this.props.history.goForward()
38   }
39 
40   render () {
41     const path = this.props.match.path
42 
43     return (
44       <div>
45         <ul>
46           {
47             this.state.messages.map((m, index) => {
48               return (
49                 <li key={index}>
50                   <Link to={`${path}/${m.id}`}>{m.title}</Link>
51                   &nbsp;&nbsp;&nbsp;
52                   <button onClick={() => this.ShowDetail(m.id)}>查看详情(push)</button>&nbsp;
53                   <button onClick={() => this.ShowDetail2(m.id)}>查看详情(replace)</button>
54                 </li>
55               )
56             })
57           }
58         </ul>
59         <p>
60           <button onClick={this.back}>返回</button>&nbsp;
61           <button onClick={this.forward}>前进</button>&nbsp;
62         </p>
63         <hr/>
64         <Route path={`${path}/:id`} component={MessageDetail}></Route>
65       </div>
66     )
67   }
68 }

View Code

路由点击刷新页面直接刷新页面页面跳转

 1  //直接刷新
 2   showDetail1(id){
 3     this.props.history.push("/home/message/messagedetail/"+id);
 4   }
 5   //直接刷新
 6   showDetail2(id){
 7     this.props.history.replace("/home/message/messagedetail/"+id);
 8   }
 9   //前进
10   goForward(){
11     this.props.history.goForward();
12   }
13   //前进
14   goback(){
15     this.props.history.goBack();
16   }
17   //页面跳转
18   reqPage(){
19     window.location='http://www.baidu.com';
20   }

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原文地址：https://www.cnblogs.com/lixiuming521125/p/16663200.html

一、react基本应用

一、helloworld(可直接用浏览器打开文件即可)

两种方式，实现react hello world；

数组用列表形式显示：

组件编程的基本定义和使用：

简单组件实现结合props的相关说明

复杂组件的相关说明：state的状态和将新增的方法强制绑定为组件对象；

ref、事件event获取元素的值

组件化编程

获取表单数据：

组件的生命周期

1. 组件的三个生命周期状态:

2. 生命周期流程:

3. 常用的方法

组件模板：

axios 请求

组件之间的参数传递：

react-router:

嵌套路由：

传参：

路由点击刷新页面 直接刷新页面 页面跳转

路由点击刷新页面直接刷新页面页面跳转