React functional component setState未更新状态

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>
  );
}

import React, { useState } from 'react';

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

  const handleClick = () => {
    setCount(prevCount => prevCount + 1, () => {
      console.log('Count updated:', count);
    });
  };

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

import React, { useState } from 'react';

function MyComponent() {
  const [person, setPerson] = useState({ name: 'John', age: 25 });

  const handleClick = () => {
    setPerson(prevPerson => ({
      ...prevPerson,
      age: prevPerson.age + 1
    }));
  };

  return (
    <div>
      <p>Name: {person.name}</p>
      <p>Age: {person.age}</p>
      <button onClick={handleClick}>Increment Age</button>
    </div>
  );
}