51 lines
911 B
JavaScript
51 lines
911 B
JavaScript
import React from "react";
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import Child from "./component/Child"
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// 类组件
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class App extends React.Component {
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constructor() {
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super();
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// 主要做一些初始化操作，例如该组件的状态
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this.state = {
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value : 1
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}
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console.log("constructor");
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}
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clickHandle=()=>{
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this.setState({
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value : this.state.value + 1
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})
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}
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componentDidUpdate(){
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// 更新后调用
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console.log("componentDidUpdate");
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}
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componentDidMount(){
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console.log("componentDidMount");
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// 接下来就可以在这里发送 ajax 请求，获取绑定计时器之类的操作
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}
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render() {
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console.log("render");
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return (
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<div>
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<div>{this.state.value}</div>
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<button onClick={this.clickHandle}>+1</button>
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{
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this.state.value % 2 === 0 ? null : <Child/>
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}
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</div>
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)
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}
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}
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export default App;
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