如何使用expo和react-native将照片从firebase存储保存到手机画廊？

import * as firebase from 'firebase';
import 'firebase/firestore';

const firebaseConfig = {
  // 将Firebase配置信息填入此处
};

if (!firebase.apps.length) {
  firebase.initializeApp(firebaseConfig);
}

import { Permissions } from 'expo-permissions';
import * as ImagePicker from 'expo-image-picker';

// 在组件初始化时请求权限
useEffect(() => {
  (async () => {
    const { status } = await Permissions.askAsync(Permissions.CAMERA_ROLL);
    if (status !== 'granted') {
      console.error('无法访问相册权限！');
    }
  })();
}, []);

const uploadImage = async (uri) => {
  const response = await fetch(uri);
  const blob = await response.blob();
  
  const storageRef = firebase.storage().ref().child('images');
  const imageRef = storageRef.child('myimage.jpg');
  
  await imageRef.put(blob);
  const imageUrl = await imageRef.getDownloadURL();

  // 保存图片到画廊
  const savedImage = await MediaLibrary.createAssetAsync(imageUrl);
  console.log('图片已保存到画廊！');
};

const pickImage = async () => {
  const { status } = await ImagePicker.requestCameraRollPermissionsAsync();
  if (status !== 'granted') {
    console.error('无法访问相册权限！');
    return;
  }

  const result = await ImagePicker.launchImageLibraryAsync();

  if (!result.cancelled) {
    uploadImage(result.uri);
  }
};

// 在组件中调用pickImage函数以选择照片