React Render 无法在组件内部工作

Question

我正在创建一个简单的 React 组件，它会在单击按钮时更新自己的数据。令人困惑的是，html 不会自动更新，所以我手动调用 render() 函数。但即使这样也不会更新 html。我如何告诉 React 重新渲染组件？

class Ideas extends React.Component {

  constructor() {
    super()
    this.title = "My ideas"
  }

  changeIdeas(){
    this.title = "No more ideas for today"

    // how to re-render the new title? This is not working
    this.render()

    // also not working
    ReactDOM.render(<Ideas/>, window.root)
  }

  render() {
    return (
      <div>
        <h1>{this.title}</h1>
        <button onClick={this.changeIdeas}>Change ideas</button> 
      </div>                          
    )
  }
}

ReactDOM.render(<Ideas/>, window.root);

Answer 1

您需要将标题存储在状态上，而不是将其保存为实例变量。这将确保变量被 React 跟踪，并且组件将在更改时正确更新。

constructor() {
  super()
  this.state = { title: "My ideas" }
}

changeIdeas = () => {
  this.setState({
    title: "No more ideas for today"
  });
}

render() {
    return (
      <div>
        <h1>{this.state.title}</h1>
        <button onClick={this.changeIdeas}>Change ideas</button> 
      </div>                          
    )
  }

React Render 无法在组件内部工作

React Render not working from inside component

reactjs

react-component