如何將圖像存儲在 flutter 火庫中並顯示它

Question

試圖將圖像存儲在圖書收藏 flutter 但不讓我稍后存儲和檢索它。 請幫我追蹤錯誤。 問題在於coverImage 不允許我將圖像URL 存儲在firebase 中，以便以后獲取圖像時可以顯示該圖像。

 if (name != null &&
                  price != null &&
                  author != null &&
                  description != null &&
                  discountpercentage != null &&
                  rating != null) {
                if (action == 'create') {
                  await books_collection.add({
                    "name": name,
                    "price": price,
                    "author": author,
                    "description": description,
                    "discountpercentage": discountpercentage,
                    "rating": rating,
                    "createdAt": Timestamp.now(),
                   "coverImage": Timestamp.now(),

                    //            "url": uploadFilterImage()
                  });
                }

                if (action == 'update') {
                  // Update the product
                  await books_collection.doc(documentSnapshot!.id).update({
                    "name": name,
                    "price": price,
                    "author": author,
                    "description": description,
                    "discountpercentage": discountpercentage,
                    "rating": rating,
                    "createdAt": Timestamp.now(),
                     "coverImage": uploadFilterImage()
                  });
            




    Future<String> uploadFilterImage() async {
        String url = "";
        final ImagePicker _picker = ImagePicker();
        XFile? image = await _picker.pickImage(source: ImageSource.gallery);
        Uint8List fileBytes = await image!.readAsBytes();
        if (fileBytes != null) {
          final _firebaseStorage = FirebaseStorage.instance;
          var name = Timestamp.now().millisecondsSinceEpoch;
          print("$name");
          var snapshot = _firebaseStorage.ref().child('$name');
          print("$name");
          TaskSnapshot task = await snapshot.putData(
            fileBytes,
            SettableMetadata(contentType: 'image/jpeg'),
          );
          url = await task.ref.getDownloadURL();
          if (url.isNotEmpty) {
            Get.snackbar("successfull", "image uploaded");
          }
        }
        return url;
      }

Answer 1

您需要await uploadFilterImage()調用以處理異步 function 並且不返回 Future，而是返回最終值。 您的create和update案例也是如此。

await books_collection.doc(documentSnapshot!.id).update({
  "name": name,
  "price": price,
  "author": author,
  "description": description,
  "discountpercentage": discountpercentage,
  "rating": rating,
  "createdAt": Timestamp.now(),
  "coverImage": await uploadFilterImage() // here
});