Question

无法通过该函数声明setState。而且我不明白这是什么错误。

import React, { Component } from 'react';
export default class App extends Component {
  state = {
    text: ' ',
  };

  render() {
    const text = () => {
      this.setState({ text: 'Good afternoon' });
    };

    return(

    )
  }
}

Answer 1

Functions和setState应该在渲染生命周期之外。更多信息：https://reactjs.org/docs/state-and-lifecycle.html

SetState指南：https://blog.logrocket.com/an-imperative-guide-to-setstate-in-react-b837ceaf8304/

import React, { Component } from 'react';
export default class App extends Component {

state = {      
      text: " "
   }

const text = () => {
         this.setState({text: "Good afternoon"})
      }

   render() {

return(

)

}
}

Answer 2

请将功能文本置于渲染功能之外。

export default class App extends Component {
state = {
    text: ' ',
};

//function in here
text = () => {
    this.setState({ text: 'Good afternoon' });
}


render() {

    return ()
}

}

Answer 3

无论如何，当我传递函数的文本超出呈现限制时，setState不起作用。

通过函数声明setState

3 个答案: