react组件基本用法示例小结
程序员文章站
2022-12-06 23:04:33
本文实例讲述了react组件基本用法。分享给大家供大家参考，具体如下：组件间传值： &l...
本文实例讲述了react组件基本用法。分享给大家供大家参考，具体如下：
组件间传值：
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>test</title>
</head>
<body>
<div id="app">
</div>
<script src="../js/react.production.min.js"></script><!--react核心库-->
<script src="../js/react-dom.production.min.js"></script><!--操作dom的react扩展库-->
<script src="../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 id="app"></div>
<script src="../js/react.production.min.js"></script><!--react核心库-->
<script src="../js/react-dom.production.min.js"></script><!--操作dom的react扩展库-->
<script src="../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 id="app"></div>
<script src="../js/react.production.min.js"></script><!--react核心库-->
<script src="../js/react-dom.production.min.js"></script><!--操作dom的react扩展库-->
<script src="../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 id="app"></div>
<script src="../js/react.production.min.js"></script><!--react核心库-->
<script src="../js/react-dom.production.min.js"></script><!--操作dom的react扩展库-->
<script src="../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>
希望本文所述对大家react程序设计有所帮助。