将数据发送到 Firebase 实时数据库而不删除现有数据

Question

我使用 Firebase 存储来存储图像文件，当我尝试将其发送到实时数据库时，数据重写了整个数据，因此我现有的数据消失了，仅由图像 URL 数据替换。 如何在不删除现有数据的情况下发送它？

这是我的代码：

public class Utama extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {


    DrawerLayout drawerLayout;
    private Button uploadBTN;
    private ImageView imageView;
    private ProgressBar progressBar;
    private TextView namapengguna, emailpengguna;
    private View headerView;


    private FirebaseUser user;
    private DatabaseReference root;
    private StorageReference reference;
    private Uri imageUri;


    private String userID;

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

        drawerLayout = findViewById(R.id.drawer_layout);
        NavigationView navigationView = findViewById(R.id.nav_view);
        headerView = navigationView.getHeaderView(0);
        uploadBTN = findViewById(R.id.upload_btn);
        progressBar = findViewById(R.id.progressBar);
        imageView = findViewById(R.id.imageview);

        namapengguna = (TextView) headerView.findViewById(R.id.namalengkap);
        emailpengguna = (TextView) headerView.findViewById(R.id.emailpengguna);

        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(Utama.this, "Please Select Image", Toast.LENGTH_SHORT).show();
                }
            }
        });

        user = FirebaseAuth.getInstance().getCurrentUser();
        root = FirebaseDatabase.getInstance().getReference("Users");
        reference = FirebaseStorage.getInstance().getReference();
        userID = user.getUid();

        final TextView fullNameTextView = (TextView) findViewById(R.id.fullName);
        final TextView emailTextView = (TextView) findViewById(R.id.emailaddress);

        root.child(userID).addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot snapshot) {
                User userProfile = snapshot.getValue(User.class);

                if (userProfile != null) {
                    String fullName = userProfile.fullname;
                    String email = userProfile.email;

                    fullNameTextView.setText(fullName);
                    namapengguna.setText(fullName);
                    emailTextView.setText(email);
                    emailpengguna.setText(email);
                }
            }


            @Override
            public void onCancelled(@NonNull DatabaseError error) {
                Toast.makeText(Utama.this, "Terjadi Kesalahan Pada Database", Toast.LENGTH_LONG).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) {
        StorageReference fileRef = reference.child(System.currentTimeMillis() + "." + getFileExtension(uri));
        fileRef.putFile(uri).addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
            @Override
            public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
                Task<Uri> uriTask = taskSnapshot.getStorage().getDownloadUrl();
                while (!uriTask.isSuccessful());
                final Uri downloadUri = uriTask.getResult();

                if (uriTask.isSuccessful()){
                    HashMap<String,Object> result = new HashMap<>();
                    result.put(userID,downloadUri.toString());

                    root.child(userID).updateChildren(result).addOnSuccessListener(new OnSuccessListener<Void>() {
                        @Override
                        public void onSuccess(Void aVoid) {
                            progressBar.setVisibility((View.INVISIBLE));
                            Toast.makeText(Utama.this, "Your Profile succesfully changed", Toast.LENGTH_SHORT).show();
                            imageView.setImageResource(R.drawable.ic_add_photo);
                        }
                    })
                            .addOnFailureListener(new OnFailureListener() {
                                @Override
                                public void onFailure(@NonNull Exception e) {
                                    progressBar.setVisibility(View.INVISIBLE);
                                    Toast.makeText(Utama.this, "", Toast.LENGTH_SHORT).show();
                                }
                            });
                }
//                fileRef.getDownloadUrl().addOnSuccessListener(new OnSuccessListener<Uri>() {
//                    @Override
//                    public void onSuccess(Uri uri) {
//                        Model model = new Model(uri.toString());
//                        String modelId = root.push().getKey();
////                        root.child(userID).child(modelId).setValue(model);
//                        root.child(userID).child(modelId).setValue(model);
//                        progressBar.setVisibility(View.INVISIBLE);
//                        Toast.makeText(Utama.this, "Upload Succesfully", Toast.LENGTH_SHORT).show();
//                        imageView.setImageResource(R.drawable.ic_add_photo);
//                    }
//                });
            }
        })
//                .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(Utama.this,e.getMessage(), Toast.LENGTH_SHORT).show();
            }
        });
    }

    private String getFileExtension(Uri mUri) {

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


    public void ClickMenu(View view) {
        Dashboard.openDrawer(drawerLayout);
    }

    public void ClickLogo(View view) {
        Dashboard.closeDrawer(drawerLayout);
    }

    public void ClickHome(View view) {
        Dashboard.redirectActivity(this, Dashboard.class);
    }

    public void ClickUtama(View view) {
        recreate();
    }

    public void ClickAboutUs(View view) {
        Dashboard.redirectActivity(this, AboutUs.class);
    }

    public void ClickLogout(View view) {
        logout (this);
    }

    private void redirectActivity(Activity activity, Class aClass) {
        Intent intent = new Intent(activity, aClass);
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        activity.startActivity(intent);
    }

    public static void logout(Activity activity) {
        AlertDialog.Builder builder = new AlertDialog.Builder(activity);
        builder.setTitle("Logout");
        builder.setMessage("Are you sure want to logout?");
        builder.setPositiveButton("YES", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                activity.finishAffinity();
                System.exit(0);
            }
        });

        builder.setNegativeButton("No", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();
            }
        });

        builder.show();

    }

    @Override
    protected void onPause() {
        super.onPause();
        Dashboard.closeDrawer(drawerLayout);
    }


    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
        return false;
    }
}

这是针对Model的：

public class Model {

    private  String imageUrl;
    public String fullname, email;

    public Model (){

    }

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

    }

    public String getImageUrl() {
        return imageUrl;
    }

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

这是问题如何重命名图像

Answer 1

您必须使用 setValue 将值设置为您的实时数据库。 您正在使用的当前方法替换 userId 下的已完成数据，但如果您希望更新特定字段，您应该

root.child("users").child(userId).setValue(user)

使用这样的东西。

Answer 2

这是问题如何重命名图像

无需重命名图像。 您甚至可以从一开始就正确更新它。 当您向 Firebase 添加数据时，您的结构如下所示：

Firebase-root
   |
   --- Users
        |
        --- Pp3Cc... smV2
              |
              --- email: "test@gmail.com"
              |
              --- fullname: "Test"

现在，要在 UID 的节点中添加一个名为“imageUrl”的新属性，它可以保存照片的实际 URL，请更改以下代码行：

result.put(userID,downloadUri.toString());

至：

result.put("imageUrl",downloadUri.toString());

这样，您的第一个孩子不会被添加为：

Firebase-root
   |
   --- Users
        |
        --- Pp3Cc... smV2
              |
              --- Pp3Cc... smV2: "https://" //Incorrect
              |
              --- email: "test@gmail.com"
              |
              --- fullname: "Test"

但是作为：

Firebase-root
   |
   --- Users
        |
        --- Pp3Cc... smV2
              |
              --- imageUrl: "https://" //Correct
              |
              --- email: "test@gmail.com"
              |
              --- fullname: "Test"