如何在ReactJS上触发组件的状态更改？

class MyComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = { count: 0 };
  }

  handleClick() {
    this.setState({ count: this.state.count + 1 });
  }

  render() {
    return (
      <div>
        <p>Count: {this.state.count}</p>
        <button onClick={() => this.handleClick()}>Increment</button>
      </div>
    );
  }
}

class ParentComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = { count: 0 };
  }

  handleStateChange(newState) {
    this.setState({ count: newState });
  }

  render() {
    return (
      <div>
        <ChildComponent onStateChange={(newState) => this.handleStateChange(newState)} />
        <p>Count: {this.state.count}</p>
      </div>
    );
  }
}

class ChildComponent extends React.Component {
  handleClick() {
    // 假设在某个事件中触发状态更改
    this.props.onStateChange(5); // 通知父组件进行状态更改
  }

  render() {
    return (
      <button onClick={() => this.handleClick()}>Change State</button>
    );
  }
}

import React, { useState } from 'react';

function MyComponent() {
  const [count, setCount] = useState(0);

  const handleClick = () => {
    setCount(count + 1);
  };

  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={handleClick}>Increment</button>
    </div>
  );
}