在 React 中的 onClick 事件之后渲染多个元素

Question

在onClick事件后，我在尝试在反应组件中渲染两个反应元素时遇到问题。想知道这是否可能吗？我确定我搞砸了三元运算符，但我无法思考另一种方法来做我想做的事情？

TL;DR：">当我点击一个按钮时，我看到元素A和元素B">

下面是一段代码：

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;

Answer 1

你只是不专心。

elementA() {
return ( // You forget
<div>
<h1>
some data
</h1>
</div>
)
}

元素 B 也是如此。

如果你想看到这两个组件，你应该把你的三元改为

{ this.state.showElement
?
<div> {this.elementA()} {this.elementB()}</div>
:
null
}

另一个"和"，用于在state中切换showElement恰到好处this.setState({showElement: !this.state.showElement });

Answer 2

试试这个，(我将在代码中添加注释，试图解释发生了什么(：

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;