我正在开发一个应用程序，我试图将我的图像添加到实时数据库中的存储和图像URL中，但当我试图上传时，它说失败了。我不明白为什么会发生这种情况。请调查一下，并指导我为什么会发生这种情况。我是新来的安卓系统，所以对我来说有点难以理解。请调查一下。谢谢
主要活动代码

public class MainActivity extends AppCompatActivity {

//widgets
private Button uploadBtn;
private ImageView imageView;
private ProgressBar progressBar;

private DatabaseReference databasereference = FirebaseDatabase.getInstance().getReference("Image");
private StorageReference storagereference = FirebaseStorage.getInstance().getReference();
private Uri imageUri;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    uploadBtn = findViewById(R.id.fabUploadImage);
    progressBar = findViewById(R.id.progressBar);
    imageView = findViewById(R.id.no_image);

    progressBar.setVisibility(View.INVISIBLE);
    
    imageView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent galleryIntent = new Intent();
            galleryIntent.setAction(Intent.ACTION_GET_CONTENT);
            galleryIntent.setType("image/*");
            startActivityForResult(galleryIntent , 2);
        }
    });

    uploadBtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (imageUri != null){
                uploadToFirebase(imageUri);
            }else{
                Toast.makeText(MainActivity.this, "Please Select Image", Toast.LENGTH_SHORT).show();
            }
        }
    });
}

@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (requestCode ==2 && resultCode == RESULT_OK && data != null){

        imageUri = data.getData();
        imageView.setImageURI(imageUri);

    }
}

private void uploadToFirebase(Uri uri){

    final StorageReference fileRef = storagereference.child(System.currentTimeMillis() + "." + getFileExtension(uri));
    fileRef.putFile(uri).addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
        @Override
        public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
            fileRef.getDownloadUrl().addOnSuccessListener(new OnSuccessListener<Uri>() {
                @Override
                public void onSuccess(Uri uri) {

                    Model model = new Model(uri.toString());
                    String modelId = databasereference.push().getKey();
                    databasereference.child(modelId).setValue(model);
                    progressBar.setVisibility(View.INVISIBLE);
                    Toast.makeText(MainActivity.this, "Uploaded Successfully", Toast.LENGTH_SHORT).show();
                    imageView.setImageResource(R.drawable.ic_iamge);
                }
            });
        }
    }).addOnProgressListener(new OnProgressListener<UploadTask.TaskSnapshot>() {
        @Override
        public void onProgress(@NonNull UploadTask.TaskSnapshot snapshot) {
            progressBar.setVisibility(View.VISIBLE);
        }
    }).addOnFailureListener(new OnFailureListener() {
        @Override
        public void onFailure(@NonNull Exception e) {
            progressBar.setVisibility(View.INVISIBLE);
            Toast.makeText(MainActivity.this, "Uploading Failed !!", Toast.LENGTH_SHORT).show();
        }
    });
}

private String getFileExtension(Uri mUri){

    ContentResolver cr = getContentResolver();
    MimeTypeMap mime = MimeTypeMap.getSingleton();
    return mime.getExtensionFromMimeType(cr.getType(mUri));

}

}
我的模型类

public class Model {

private String imageUrl;

public Model()
{

}

public Model(String imageUrl)
{
    this.imageUrl = imageUrl;
}

public String getImageUrl() {
    return imageUrl;
}

public void setImageUrl(String imageUrl) {
    this.imageUrl = imageUrl;
}

}