在React Native(Expo)中设置异步函数内的状态

import React, { useState, useEffect } from 'react';
import { View, Text, StyleSheet } from 'react-native';

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

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

    fetchData();
  }, []);

  if (loading) {
    return <Text>Loading...</Text>;
  }

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

  return (
    <View style={styles.container}>
      <Text>Data: {JSON.stringify(data)}</Text>
    </View>
  );
};

const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
  },
});

export default App;

setData(prevData => ({ ...prevData, newKey: newValue }));

try {
  const response = await fetch('https://api.example.com/data');
  const result = await response.json();
  setData(result);
} catch (err) {
  setError(err);
}

const memoizedData = useMemo(() => {
  return computeExpensiveValue(data);
}, [data]);