React在等待API调用返回数据时实现活动轮子

import React, { useState, useEffect } from 'react';
import axios from 'axios';

const DataFetchingComponent = () => {
  const [data, setData] = useState(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState(null);

  useEffect(() => {
    const fetchData = async () => {
      try {
        const response = await axios.get('https://api.example.com/data');
        setData(response.data);
      } catch (err) {
        setError(err);
      } finally {
        setLoading(false);
      }
    };

    fetchData();
  }, []);

  if (loading) {
    return <div>Loading...</div>; // 这里可以替换为更复杂的加载指示器
  }

  if (error) {
    return <div>Error: {error.message}</div>;
  }

  return (
    <div>
      {data ? (
        <ul>
          {data.map(item => (
            <li key={item.id}>{item.name}</li>
          ))}
        </ul>
      ) : (
        <div>No data available</div>
      )}
    </div>
  );
};

export default DataFetchingComponent;

try {
  const response = await axios.get('https://api.example.com/data');
  console.log('Data fetched:', response.data); // 添加日志
  setData(response.data);
} catch (err) {
  console.error('Error fetching data:', err); // 添加日志
  setError(err);
} finally {
  setLoading(false);
}

const fetchData = useCallback(async () => {
  try {
    const response = await axios.get('https://api.example.com/data');
    setData(response.data);
  } catch (err) {
    setError(err);
  } finally {
    setLoading(false);
  }
}, []);

useEffect(() => {
  fetchData();
}, [fetchData]);