[英]rendering multiple elements after onClick event in React
我遇到一个问题,试图在onClick
事件之后在react组件内呈现两个react元素。 想知道这是否有可能? 我确定我搞砸了三元运算符,但是我无法想到另一种方法来做我想做的事情?
TL; DR :“单击按钮时,我看到elementA 和 elementB”
这是代码片段:
import React, { Component } from 'react';
class MyComponent extends Component {
constructor(props) {
super(props)
this.state = { showElement: true };
this.onHandleClick = this.onHandleClick.bind(this);
}
onHandleClick() {
console.log(`current state: ${this.state.showElement} and prevState: ${this.prevState}`);
this.setState(prevState => ({ showElement: !this.state.showElement }) );
};
elementA() {
<div>
<h1>
some data
</h1>
</div>
}
elementB() {
<div>
<h1>
some data
</h1>
</div>
}
render() {
return (
<section>
<button onClick={ this.onHandleClick } showElement={this.state.showElement === true}>
</button>
{ this.state.showElement
?
null
:
this.elementA() && this.elementB()
}
</section>
)
}
}
export default MyComponent;
你只是不专心。
elementA() {
return ( // You forget
<div>
<h1>
some data
</h1>
</div>
)
}
与元素B相同。
如果您想同时查看这两个组件,则应将三元组更改为
{ this.state.showElement
?
<div> {this.elementA()} {this.elementB()}</div>
:
null
}
另一个“和”,用于在state
切换showElement
就足够了this.setState({showElement: !this.state.showElement });
请尝试以下操作(我将在代码中添加注释,以解释发生了什么事情):
function SomeComponentName() { // use props if you want to pass some data to this component. Meaning that if you can keep it stateless do so.
return (
<div>
<h1>
some data
</h1>
</div>
);
}
class MyComponent extends Component {
constructor(props) {
super(props)
this.state = { showElement: false }; // you say that initially you don't want to show it, right? So let's set it to false :)
this.onHandleClick = this.onHandleClick.bind(this);
}
onHandleClick() {
this.setState(prevState => ({ showElement: !prevState.showElement }) );
// As I pointed out in the comment: when using the "reducer" version of `setState` you should use the parameter that's provided to you with the previous state, try never using the word `this` inside a "reducer" `setState` function
};
render() {
return (
<section>
<button onClick={ this.onHandleClick } showElement={this.state.showElement === false}>
</button>
{ this.state.showElement
? [<SomeComponentName key="firstOne" />, <SomeComponentName key="secondOne" />]
: null
}
</section>
)
}
}
export default MyComponent;
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