<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>test</title> </head> <body> <div> </div> <script src="https://www.jb51.net/js/react.production.min.js"></script><!--react核心库--> <script src="https://www.jb51.net/js/react-dom.production.min.js"></script><!--操作DOM的react扩展库--> <script src="https://www.jb51.net/js/babel.min.js"></script><!--解析JSX语法--> <script type="text/babel"> class Com extends React.Component { click = ()=>{ // console.log(this.input); // console.log(this.p.innerText); console.log(this.refs.my.value);//父组件访问子组件用refs }; render() { return ( <div> <input type="text" ref={(input)=>{this.input=input}}/> <p ref={(p)=>{this.p=p}}>我是段落</p> <input type="text" ref="my"/> <button onClick={this.click}>点击</button> </div> ); } } ReactDOM.render(<Com/>,document.getElementById('app')); </script> </body> </html>
列表：
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>test</title> </head> <body> <div></div> <script src="https://www.jb51.net/js/react.production.min.js"></script><!--react核心库--> <script src="https://www.jb51.net/js/react-dom.production.min.js"></script><!--操作DOM的react扩展库--> <script src="https://www.jb51.net/js/babel.min.js"></script><!--解析JSX语法--> <script type="text/babel"> class Add extends React.Component { click = ()=>{ this.props.allAdd(this.input.value); }; render() { const {length} = this.props; return ( <div> <input type="text" ref={(input)=>{this.input=input}}/> <button onClick={this.click}>add{length}</button> </div> ) } } class List extends React.Component { render() { const {list} = this.props; return ( <div> <ul> { list.map((v,i)=>{ return <li key={i}>{v}</li> }) } </ul> </div> ) } } class App extends React.Component { state = { list:['吃饭','睡觉','打游戏','游泳'] }; add = (value)=>{ const {list} = this.state;//获取原先的list list.unshift(value);//将添加的值传入list this.setState(list);//重新设置list }; render() { const {list} = this.state;//获取list return ( <div> <Add allAdd={this.add} length={list.length}/> <List list={list} /> </div> ) } } ReactDOM.render(<App />,document.getElementById('app')); </script> </body> </html>
受控组件和非受控组件：
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>test</title> </head> <body> <div></div> <script src="https://www.jb51.net/js/react.production.min.js"></script><!--react核心库--> <script src="https://www.jb51.net/js/react-dom.production.min.js"></script><!--操作DOM的react扩展库--> <script src="https://www.jb51.net/js/babel.min.js"></script><!--解析JSX语法--> <script type="text/babel"> class Com extends React.Component { state = { age:'' }; //非受控组件 不受state控制 click = () => { console.log(this.input.value); }; change = (event)=>{ console.log(event.target.value); this.setState({ age: event.target.value }) }; render() { const {age} = this.props; return ( <div> 姓名：<input type="text" ref={(input)=>{this.input=input}}/> <button onClick={this.click}>获取姓名</button> 年龄：<input type="text" value={age} onChange={this.change}/> </div> ); }; } ReactDOM.render(<Com />,document.getElementById('app')); </script> </body> </html>
组件生命周期：
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Test</title> </head> <body> <div></div> <script src="https://www.jb51.net/js/react.production.min.js"></script><!--react核心库--> <script src="https://www.jb51.net/js/react-dom.production.min.js"></script><!--操作DOM的react扩展库--> <script src="https://www.jb51.net/js/babel.min.js"></script><!--解析JSX语法--> <script type="text/babel"> class Com extends React.Component { state = { msg:123 }; sing() { return new Promise((resolve,reject)=>{ setTimeout(()=>{ resolve('唱一首歌'); },1000); }) }; async get() { await this.sing().then((res)=>{ console.log(res); }); }; componentWillMount() { //will会先执行，但不一定先执行完毕 console.log('之前'); // this.get(); } componentDidMount() { //进行ajax操作，获取后台数据 console.log('之后'); } shouldComponentUpdate(nextProps, nextState) { const {msg} = this.state; //如果没有 if ({msg} !== nextState) { return true; } console.log('更新'); return false; } componentWillUpdate() { console.log('更新之前'); } componentDidUpdate() { console.log('更新之后'); //再次获取数据 } click = ()=>{ this.setState({ msg: 234 }) }; render() { console.log('render'); const {msg} = this.state; return( <div> <h1>{msg}</h1> <button onClick={this.click}>更新</button> </div> ) } } ReactDOM.render(<Com />,document.getElementById('app')); </script> </body> </html>