我知道如何使用React.createRef()访问dom的单个元素。但是我想使用createRef访问两个不同的元素。我已经看到了一些关于stackoverflow的示例,该示例可以动态访问多个元素但无法理解。我在这里附加了我的简单代码,我想在其中更改span标签onClick的背景颜色。接下来,我对React Docs进行了反应。有人可以指导我,我在这里做错了什么。
class TodoApp extends React.Component {
constructor(props) {
super(props)
// this.myRef = React.createRef();
this.textInput = null;
this.state = {
fname:""
}
}
setTextInputRef = element => {
console.log("element",element);
this.textInput = element;
};
green = () =>{
console.log("green ",this.textInput);
/* this.textInput.current.style.backgroundColor = "green"; */
this.textInput.style.backgroundColor = "green";
}
red = () =>{
console.log("red ",this.textInput);
/* this.textInput.current.style.backgroundColor = "red"; */
this.textInput.style.backgroundColor = "red";
}
render() {
return (
<div>
{/*
<span id="green" ref={input => { this.setTextInputRef = input; }}>Green</span><br/>
<span id="red" ref={input => { this.setTextInputRef = input; }}>Red</span><br/>
*/}
<span id="green" ref={this.setTextInputRef}>Green</span><br/>
<span id="red" ref={this.setTextInputRef}>Red</span><br/>
<button onClick={this.green}>For Green</button><br/>
<button onClick={this.red}>For Red</button><br/>
</div>
)
}
}
ReactDOM.render(<TodoApp />, document.querySelector("#app"))
在上面的代码中,如果用户单击btn,则应更改相应的跨度颜色。
任何帮助将不胜感激。
如果渲染的元素是静态的,则可以在构造函数中创建多个引用,并使用this.myRef.current
访问这些元素>
您的带有createRef的代码如下所示
import React from "react";
import "./styles.css";
export default class TodoApp extends React.Component {
constructor(props) {
super(props);
this.greenInputRef = React.createRef();
this.redInputRef = React.createRef();
this.state = {
fname: ""
};
}
green = () => {
console.log("green ", this.textInput);
/* this.textInput.current.style.backgroundColor = "green"; */
this.greenInputRef.current.style.backgroundColor = "green";
};
red = () => {
console.log("red ", this.textInput);
/* this.textInput.current.style.backgroundColor = "red"; */
this.redInputRef.current.style.backgroundColor = "red";
};
render() {
return (
<div>
{/*
<span id="green" ref={input => { this.setTextInputRef = input; }}>Green</span><br/>
<span id="red" ref={input => { this.setTextInputRef = input; }}>Red</span><br/>
*/}
<span id="green" ref={this.greenInputRef}>
Green
</span>
<br />
<span id="red" ref={this.redInputRef}>
Red
</span>
<br />
<button onClick={this.green}>For Green</button>
<br />
<button onClick={this.red}>For Red</button>
<br />
</div>
);
}
}
如果要通过循环动态呈现代码段,则可以按以下方式创建引用
constructor(props) {
super(props);
props.data.forEach(item => {
this[`dataRef${item.id}] = React.createRef();
})
}
...
render() {
return (
<div>
{
data.map(item =>
<p ref={this[`dataRef{item.id}]}>{item.name}</p>
)
}
</div>
)
}