无法在 Firebase Firestore 中存储下载 URL

Question

我正在尝试将图像存储到 Firebase 存储中，然后从 Firebase 存储中下载这些图像的 URI，然后使用 foreach 循环再次将这些 URI 上传到 firebase firestore。图像已成功上传到 Firebase 存储，但只有最后一张图像的 Uri 进入 Firestore，前三个失败。我创建了一个位图数组列表，然后在其上使用了 foreach 循环。

我的代码

    private void UploadingImage() {

        if (bitmap != null && bitmap2 != null && bitmap3 != null && bitmap4 != null) {

            StorageTask arrayUpload;
            fuser = FirebaseAuth.getInstance().getCurrentUser();
            ProductName = Objects.requireNonNull(Product_Name_EditText.getText()).toString();
            CityName = Objects.requireNonNull(CityNameEditText.getText()).toString();

            // Bitmap[] bitmaps=new Bitmap[3];
            ArrayList<Bitmap> bitmapArrayList = new ArrayList<>();
            bitmapArrayList.add(bitmap);
            bitmapArrayList.add(bitmap2);
            bitmapArrayList.add(bitmap3);
            bitmapArrayList.add(bitmap4);

            Bitmap bitresized;

            for (Bitmap bitUpload : bitmapArrayList)
            {
                bitresized = Bitmap.createScaledBitmap(bitUpload, 800, 800, true);
                ByteArrayOutputStream baosArray = new ByteArrayOutputStream();
                bitresized.compress(Bitmap.CompressFormat.JPEG, 70, baosArray);
                byte[] uploadbaosarray = baosArray.toByteArray();
                i = i + 1;
                fileReference = storageReference.child(ProductName).child(i + ProductName + ".jpg");

                arrayUpload = fileReference.putBytes(uploadbaosarray);

                arrayUpload.continueWithTask(new Continuation<UploadTask.TaskSnapshot, Task<Uri>>() {
                    @Override
                    public Task<Uri> then(@NonNull Task<UploadTask.TaskSnapshot> task) throws Exception {
                        if (!task.isSuccessful()) {
                            throw task.getException();
                        } else if (task.isSuccessful()) {
                            Toast.makeText(Upload_New_Product.this, "Uploaded Successfully", Toast.LENGTH_SHORT).show();
                            //mProgressBar.setVisibility(View.INVISIBLE);
                        }

                        return fileReference.getDownloadUrl();
                    }
                }).addOnCompleteListener(new OnCompleteListener<Uri>() {
                    @Override
                    public void onComplete(@NonNull Task<Uri> task) {
                        if (task.isSuccessful()) {
                            Uri downloadUri = task.getResult();
                            assert downloadUri != null;
                            String mUri = downloadUri.toString();

                            ProductName = Product_Name_EditText.getText().toString();
                            ProductRef = db.collection("Sellers").document(CityName).collection(Uid).document(ProductName);
                            HashMap<String, Object> map = new HashMap<>();
                            map.put("imageURL" + i, mUri);
                            //reference.updateChildren(map);
                            ProductRef.set(map, SetOptions.merge());

                        } else {
                            Toast.makeText(Upload_New_Product.this, "Failed!", Toast.LENGTH_SHORT).show();
                        }
                    }
                }).addOnFailureListener(new OnFailureListener() {
                    @Override
                    public void onFailure(@NonNull Exception e) {
                        Toast.makeText(Upload_New_Product.this, e.getMessage(), Toast.LENGTH_SHORT).show();
                        //pd.dismiss();
                    }
                });

            }
        }
}

Answer 1

由于上传（和获取下载 URL）是异步操作，for 循环几乎立即完成，之后所有上传都并行进行。这意味着当您的 map.put("imageURL" + i, mUri) 运行时，i 变量将成为它的最终值。

要使代码工作，您需要捕获循环中每次迭代的i 变量。一个简单的方法是将上传图像并将其 URL 存储到一个单独的函数中的代码，并将 i 的值传递给该函数调用。

类似：

public void uploadFileAtIndex(int i) {
    fileReference = storageReference.child(ProductName).child(i + ProductName + ".jpg");

    arrayUpload = fileReference.putBytes(uploadbaosarray);

    arrayUpload.continueWithTask(new Continuation<UploadTask.TaskSnapshot, Task<Uri>>() {
        @Override
        public Task<Uri> then(@NonNull Task<UploadTask.TaskSnapshot> task) throws Exception {
            if (!task.isSuccessful()) {
                throw task.getException();
            } else if (task.isSuccessful()) {
                Toast.makeText(Upload_New_Product.this, "Uploaded Successfully", Toast.LENGTH_SHORT).show();
            }

            return fileReference.getDownloadUrl();
        }
    }).addOnCompleteListener(new OnCompleteListener<Uri>() {
        @Override
        public void onComplete(@NonNull Task<Uri> task) {
            if (task.isSuccessful()) {
                Uri downloadUri = task.getResult();
                assert downloadUri != null;
                String mUri = downloadUri.toString();

                ProductName = Product_Name_EditText.getText().toString();
                ProductRef = db.collection("Sellers").document(CityName).collection(Uid).document(ProductName);
                HashMap<String, Object> map = new HashMap<>();
                map.put("imageURL" + i, mUri);
                ProductRef.set(map, SetOptions.merge());
            } else {
                Toast.makeText(Upload_New_Product.this, "Failed!", Toast.LENGTH_SHORT).show();
            }
        }
    }).addOnFailureListener(new OnFailureListener() {
        @Override
        public void onFailure(@NonNull Exception e) {
            Toast.makeText(Upload_New_Product.this, e.getMessage(), Toast.LENGTH_SHORT).show();
        }
    });
}

然后在循环中使用它：

for (Bitmap bitUpload : bitmapArrayList) {
    ...
    i = i + 1;
    uploadFileAtIndex(i);
}

您可能需要将更多的变量传递给uploadFileAtIndex，而不是我在此处所做的，但传递i 可以解决您现在遇到的问题。