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生命周期回调函数----生命周期钩子函数-----生命周期函数
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>引出生命周期.</title>
</head>
<body>
<!-- 准备一个容器 -->
<div id="test"></div>
<!-- 引入react核心库 -->
<script src="https://cdn.bootcdn.net/ajax/libs/react/18.2.0/umd/react.development.min.js"></script>
<!-- 引入react-dom, 用于支持react操作dom, 需要在核心库之后引入 -->
<script src="https://cdn.bootcdn.net/ajax/libs/react-dom/18.2.0/umd/react-dom.development.min.js"></script>
<!-- 引入babel.js，用于将jsx转化为js -->
<script src="https://cdn.bootcdn.net/ajax/libs/babel-standalone/7.18.7/babel.min.js"></script>
<!-- 引入prop-types -->
<script src="https://cdn.bootcdn.net/ajax/libs/prop-types/15.8.1/prop-types.min.js"></script>
<script type="text/babel">
class Life extends React.Component {
state = { opacity: 0 };
death = () => {
// 卸载组件
ReactDOM.unmountComponentAtNode(document.getElementById('test'))
}
// 组件挂载完毕
componentDidMount() {
this.timer = setInterval(() => {
let { opacity } = this.state;
opacity -= 0.1;
console.log(opacity, 'opacity===');
if(opacity <= 0) opacity = 1;
this.setState({ opacity })
}, 200);
}
// 组件即将卸载
componentWillUnmount() {
clearInterval(this.timer)
}
render() {
return (
<div>
<h2 style={{ opacity: this.state.opacity }}>react学不会怎么办？</h2>
<button onClick={this.death}>不活了</button>
</div>
)
}
}
ReactDOM.render(<Life />, document.getElementById('test'))
</script>
</body>
</html>
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标签：opacity,生命周期,react,state,test,document From： https://www.cnblogs.com/fqh123/p/16648121.html