如何从 Firebase 存储中检索图像的下载 URL？

Question

我正在观看有关 Firebase 存储的旧教程。来自UploadTask.TaskSnapshot 的getDownloadUrl() 方法已不存在，而documentation 我也不清楚。

到目前为止，我实施的是上传过程，我可以确认它可以正常工作，但是获取 URL 很痛苦，我无法按照他们解释的方式进行操作，因为：

1) 创建Task<Uri> urlTask = uploadTask.add[...]() 会导致IDE 出现以下错误：

我不明白，因为它在文档中指定。

2) 使用reference.getDownloadUrl() 会在查看上传图片的详细信息时显示与控制台上显示的不同的 URL。控制台显示的下载地址是

https://firebasestorage.googleapis.com/v0/b/chatroom-e44e6.appspot.com/o/chat_photos%2F73185640?alt=media&token=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

同时显示日志

com.google.android.gms.tasks.xxx@xxxxxxx

我现在的完整代码：

if (requestCode == RC_PHOTO_PICKER) {
    if (data != null) {
        Toast.makeText(MainActivity.this, "Uploading...", Toast.LENGTH_SHORT).show();

        Uri file = data.getData();
        final StorageReference reference = mPhotoStorageReference.child(file.getLastPathSegment());
        UploadTask upload = reference.putFile(file);

        upload.addOnFailureListener(this, new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                Toast.makeText(MainActivity.this, "Image could not be uploaded: " + e.getMessage(), Toast.LENGTH_LONG).show();
            }
        }).addOnCompleteListener(this, new OnCompleteListener<UploadTask.TaskSnapshot>() {
            @Override
            public void onComplete(@NonNull Task<UploadTask.TaskSnapshot> task) {
                ChatroomMessage message = new ChatroomMessage(null, mUsername, reference.getDownloadUrl().toString()); // <- com.google.android.gms.tasks.xxx@xxxxxxx
                mMessagesDatabaseReference.push().setValue(message);
                Toast.makeText(MainActivity.this, "Image uploaded!", Toast.LENGTH_SHORT).show();
            }
        });
    }
}

我的应用已经实现了 Firebase UI 来处理登录操作，并且规则是

service firebase.storage {
  match /b/{bucket}/o {
    match /{allPaths=**} {
      allow read, write: if request.auth != null;
    }
  }
}

Answer 1

我付出了努力并浪费了更多时间，但这里是更通用和有效的解决方案

    private void uploadImage() {

    if (filePath != null) {
        final ProgressDialog progressDialog = new ProgressDialog(this);
        progressDialog.setTitle("Uploading...");
        progressDialog.show();
        final StorageReference ref = storageReference.child("images/" +currentFirebaseUser.getUid() + "");

        ref.putFile(filePath)
                .addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
                    @Override
                    public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
                        progressDialog.dismiss();

                        Task<Uri> urlTask = taskSnapshot.getStorage().getDownloadUrl();
                        while (!urlTask.isSuccessful());
                        Uri downloadUrl = urlTask.getResult();
                        Log.e("uri12",downloadUrl+"This is uri of image download");
                        Toast.makeText(AddItemActivity.this, "Uploaded", Toast.LENGTH_SHORT).show();
                    }
                })
                .addOnFailureListener(new OnFailureListener() {
                    @Override
                    public void onFailure(@NonNull Exception e) {
                        progressDialog.dismiss();
                        Toast.makeText(AddItemActivity.this, "Failed " + e.getMessage(), Toast.LENGTH_SHORT).show();
                    }
                })
                .addOnProgressListener(new OnProgressListener<UploadTask.TaskSnapshot>() {
                    @Override
                    public void onProgress(UploadTask.TaskSnapshot taskSnapshot) {
                        double progress = (100.0 * taskSnapshot.getBytesTransferred() / taskSnapshot
                                .getTotalByteCount());
                        progressDialog.setMessage("Uploaded " + (int) progress + "%");
                    }
                });
    }
}

Answer 2

你有Permission denied error 这意味着你没有权限从 firebase 访问数据。请看这里

如果您的安全规则是公开的，那么这里不需要许可，如果它不是公开的或安全的，那么您需要在从 firebase 获取数据之前通过 auth 登录，如果登录成功，那么您可以继续工作。

check this 它将帮助您了解 Firebase 安全规则。

Answer 3

经过多次尝试，我设法解决了它。这是实现：

Uri file = data.getData();
final StorageReference reference = mPhotoStorageReference.child(file.getLastPathSegment());
UploadTask upload = reference.putFile(file);

upload.addOnFailureListener(this, new OnFailureListener() {
    @Override
    public void onFailure(@NonNull Exception e) {
        Toast.makeText(MainActivity.this, "Image could not be uploaded: " + e.getMessage(), Toast.LENGTH_LONG).show();
    }
});

upload.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();
        }

        return reference.getDownloadUrl();
    }
}).addOnCompleteListener(new OnCompleteListener<Uri>() {
    @Override
    public void onComplete(@NonNull Task<Uri> task) {
        if (task.isSuccessful()) {
            Uri downloadUrl = task.getResult();
            ChatroomMessage message = new ChatroomMessage(null, mUsername, downloadUrl.toString());

            mMessagesDatabaseReference.push().setValue(message);

            Toast.makeText(MainActivity.this, "Image uploaded!", Toast.LENGTH_SHORT).show();
        } else {
            Toast.makeText(MainActivity.this, task.getException().toString(), Toast.LENGTH_SHORT).show();
        }
    }
});