为什么我无法在 Android Studio 中使用 ImageButton 上传图像文件？

Question

I'm trying to upload an image using Image Button. I don't get any error or crash, but after uploading my image, I get an alert: "Failed,". and the message of e.

Can you help me please?

 private void uploadImage() {
        final ProgressDialog pd = new ProgressDialog(getContext());
        pd.setMessage("Uploading");
        pd.show();

        if(imageUri != null) {
            final StorageReference fileReference = storageReference.child(System.currentTimeMillis() + "." + getFileExtension(imageUri));
            uploadTask = fileReference.getFile(imageUri);
            uploadTask.continueWith(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 fileReference.getDownloadUrl();
                }
            }).addOnCompleteListener(new OnCompleteListener<Uri>() {
                @Override
                public void onComplete(@NonNull Task<Uri> task) {

                    if(task.isSuccessful()) {
                        Uri downloadUri = task.getResult();
                        String mUri = downloadUri.toString();
                        reference = FirebaseDatabase.getInstance().getReference().child("users").child(fuser.getUid());
                        HashMap<String, Object> map = new HashMap<>();
                        map.put("imageURL", mUri);
                        reference.updateChildren(map);
                        pd.dismiss();
                    } else {
                        Toast.makeText(getContext(), "Failed!", Toast.LENGTH_SHORT).show();
                        pd.dismiss();
                    }
                }
            }).addOnFailureListener(new OnFailureListener() {
                @Override
                public void onFailure(@NonNull Exception e) {
                    Toast.makeText(getContext(), e.getMessage(), Toast.LENGTH_SHORT).show();
                    pd.dismiss();
                }
            });
        } else {
            Toast.makeText(getContext(), "No Image Selected", Toast.LENGTH_SHORT).show();
        }
    }

Answer 1

If your error message was:

Object does not exist at location

Then that means the object you're trying to download simply doesn't exist. Here's the code you're using to build that location:

final StorageReference fileReference = storageReference
    .child(System.currentTimeMillis() + "." + getFileExtension(imageUri));

So, it seems you are trying to fetch a file that's supposed to exist using a name that matches this the current moment in time. I suspect that's almost never going to work. Since we can't see the contents of your storage bucket, and we don't know the exact string you're passing here, there's no telling how to fix this. Your code should only fetch objects whose names that exist in the bucket.

Answer 2

You're not calling a fileReference.put method anywhere, which means you're not uploading any data.

So when you call fileReference.getDownloadURL() it throws an error, because there is no file at the location to return a download URL for.

I recommend reading the documentation on uploading files , and waiting for the upload to complete before trying to get the download URL.