Android Firebase How to wait for image upload before registering to database?

I am new to android development and I have an issue.

I have a fragment in which a user can post an announcement and should be able to upload a photo(optional).
When the form is full and the "Post announcement" button is pressed, I trigger the method to save the information to the database.

The only problem I am facing is retrieving the Uri of the newly uploaded photo.
This is the code which extracts the information.

public Map<String, Object> appendDataFromAnnouncementForm(){
    String title = titleLineEdit.getText().toString();
    String category = categoryLineEdit.getText().toString();
    String description = descriptionLineEdit.getText().toString();
    String date = dateLineEdit.getText().toString();
    String time = timeLineEdit.getText().toString();
    String location = locationLineEdit.getText().toString();

    //Image upload to firebase + getting the Uri

    if(localPhotoUri != null){
        uploadImageToFirebase(generatePhotoName(localPhotoUri), localPhotoUri);
    }


    Map<String, Object> newAnnouncement = new HashMap<>();

    //@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
    if(uploadedImageUri != null) // <- this is always null
    {newAnnouncement.put("imageUri", uploadedImageUri.toString());}
    //@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

    newAnnouncement.put("title", title);
    newAnnouncement.put("category", category);
    newAnnouncement.put("description", description);
    newAnnouncement.put("date", date);
    newAnnouncement.put("time", time);
    newAnnouncement.put("location", location);



    return newAnnouncement;
}

Below I am posting the code which uploads the photo to Firebase Storage. Since

private void uploadImageToFirebase(String photoName, Uri localContentUri) {
    imagesStorageReferance = myStorageReference.child("images/" + photoName);
    imagesStorageReferance.putFile(localContentUri).addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
        @Override
        public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
            //getUploadedImageUri(referenceToImageFolder);
            imagesStorageReferance.getDownloadUrl().addOnSuccessListener(new OnSuccessListener<Uri>() {
                @Override
                public void onSuccess(Uri uri) {
                    Log.d(TAG, "onSuccess: The download url of the photo is "
                            + uri.toString());
                    uploadedImageUri = uri; /// <- I want to retrieve this 
                }
            });

        }
    })
            .addOnFailureListener(new OnFailureListener() {
                @Override
                public void onFailure(@NonNull Exception e) {
                    Log.d(TAG, "onFailure: Failed uploading the photo to the database " + e.getMessage());
                }
            });
}

From what I have read on the Internet, this is an synchronization problem(basically, the app registers the information to the database before my photo is uploaded). There are many solutions which I have tried, but I can't really figure it out one to work on my case...

I would be very grateful if you could provide me some explanation on what I should do in order to fix this. How can I wait the photo to be uploaded ?

Since firebase works asynchronously, the code continues to execute regardless of whether firebase has finished the upload process or not. In your case, the time to run the code following firebase is faster than the upload time to firebase to eventually assign uploadedImageUri = uri; which explains why you are getting a null value for uploadedImageUri present directly after the call for upload.

For this matter, I would suggest you to register to database inside uploadImageToFirebase function after uploadedImageUri = uri; to ensure that uploadedImageUri is never null and always fetched before database registration.

private void uploadImageToFirebase(String photoName, Uri localContentUri) {
    imagesStorageReferance = myStorageReference.child("images/" + photoName);
    imagesStorageReferance.putFile(localContentUri).addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
        @Override
        public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
            //getUploadedImageUri(referenceToImageFolder);
            imagesStorageReferance.getDownloadUrl().addOnSuccessListener(new OnSuccessListener<Uri>() {
                @Override
                public void onSuccess(Uri uri) {
                    Log.d(TAG, "onSuccess: The download url of the photo is "
                            + uri.toString());
                    uploadedImageUri = uri;
    String title = titleLineEdit.getText().toString();
    String category = categoryLineEdit.getText().toString();
    String description = descriptionLineEdit.getText().toString();
    String date = dateLineEdit.getText().toString();
    String time = timeLineEdit.getText().toString();
    String location = locationLineEdit.getText().toString();

    Map<String, Object> newAnnouncement = new HashMap<>();

    newAnnouncement.put("imageUri", uploadedImageUri.toString());

    newAnnouncement.put("title", title);
    newAnnouncement.put("category", category);
    newAnnouncement.put("description", description);
    newAnnouncement.put("date", date);
    newAnnouncement.put("time", time);
    newAnnouncement.put("location", location);

//UPLOAD newAnouncement TO FIREBASE HERE...
                }
            });

        }
    })
            .addOnFailureListener(new OnFailureListener() {
                @Override
                public void onFailure(@NonNull Exception e) {
                    Log.d(TAG, "onFailure: Failed uploading the photo to the database " + e.getMessage());
                }
            });
}

I am sharing the code from my project:

Assign this globally:

StorageTask uploadTask;
String myUrl = "";

and this is code:

private void uploadImage()
{
    if (imageUri != null)
    {
        final StorageReference reference = storageReference.child(System.currentTimeMillis()+"."+getExtension(imageUri));
        uploadTask = reference.putFile(imageUri);
        uploadTask.continueWithTask(new Continuation() {
            @Override
            public Object then(@NonNull Task task) throws Exception {
                if (!task.isComplete())
                {
                    throw task.getException();
                }
                return reference.getDownloadUrl();
            }
        }).addOnCompleteListener(new OnCompleteListener<Uri>() {
            @Override
            public void onComplete(@NonNull Task<Uri> task) {
                if (task.isSuccessful())
                {
                    Uri downloadUri = task.getResult();
                    myUrl = downloadUri.toString();

                    DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference("Categories")
                            .child(randomKey);

                    HashMap<String, Object> hashMap = new HashMap<>();
                    hashMap.put("categoryId", randomKey);
                    hashMap.put("categoryImage", myUrl);
                    hashMap.put("categoryName", editText.getText().toString());

                    databaseReference.setValue(hashMap);

                    save.setVisibility(View.VISIBLE);
                    startActivity(new Intent(AddCategoryActivity.this, CategoriesActivity.class));
                }
                else
                {
                    save.setVisibility(View.VISIBLE);
                    Toast.makeText(AddCategoryActivity.this, "Failed!", Toast.LENGTH_SHORT).show();
                }
            }
        }).addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                save.setVisibility(View.VISIBLE);
                Toast.makeText(AddCategoryActivity.this, ""+e.getMessage(), Toast.LENGTH_SHORT).show();
            }
        });
    }
    else
    {
        save.setVisibility(View.VISIBLE);
        Toast.makeText(this, "No Image Selected", Toast.LENGTH_SHORT).show();
    }
}