Firebase Storage download file to Pictures or Movie folder in Android Q

==NEW ANSWER==

If you wanted to monitor the download progress you can use getStream() of FirebaseStorage SDK like this:

httpsReference.getStream((state, inputStream) -> {

                long totalBytes = state.getTotalByteCount();
                long bytesDownloaded = 0;

                byte[] buffer = new byte[1024];
                int size;

                while ((size = inputStream.read(buffer)) != -1) {
                    stream.write(buffer, 0, size);
                    bytesDownloaded += size;
                    showProgressNotification(bytesDownloaded, totalBytes, requestCode);
                }

                // Close the stream at the end of the Task
                inputStream.close();
                stream.flush();
                stream.close();

            }).addOnSuccessListener(taskSnapshot -> {
                showDownloadFinishedNotification(downloadedFileUri, downloadURL, true, requestCode);
                //Mark task as complete so the progress download notification whether success of fail will become removable
                taskCompleted();
                contentValues.put(MediaStore.Files.FileColumns.IS_PENDING, false);
                resolver.update(uriResolve, contentValues, null, null);
            }).addOnFailureListener(e -> {
                Log.w(TAG, "download:FAILURE", e);

                try {
                    stream.flush();
                    stream.close();
                } catch (IOException ioException) {
                    ioException.printStackTrace();
                    FirebaseCrashlytics.getInstance().recordException(ioException);
                }

                FirebaseCrashlytics.getInstance().recordException(e);

                //Send failure
                showDownloadFinishedNotification(null, downloadURL, false, requestCode);

                //Mark task as complete
                taskCompleted();
            });

==OLD ANSWER==

Finally after tons of hours I manage to do it but using .getBytes(maximum_file_size) instead of .getFile(file_object) as last resort.

Big big thanks to @Kasim for bringing up the idea of getBytes(maximum_file_size) with also sample code working with InputStream and OutputStream.By searching across S.O topic related to I/O also is a big help here and here

The idea here is .getByte(maximum_file_size) will download the file from the bucket and return a byte[] on its addOnSuccessListener callback. The downside is you must specify the file size you allowed to download and no download progress computation can be done AFAIK unless you do some work with outputStream.write(0,0,0); I tried to write it chunk by chunk like here but the solution is throwing ArrayIndexOutOfBoundsException since you must be accurate on working with index into an array.

So here is the code that let you saved file from your Firebase Storage Bucket to your device default directories: storage/emulated/0/Pictures, storage/emulated/0/Movies, storage/emulated/0/Documents, you name it

//Member variable but depending on your scope
private ByteArrayInputStream inputStream;
private Uri downloadedFileUri;
private OutputStream stream;

//Creating a reference to the link
    StorageReference httpsReference = FirebaseStorage.getInstance().getReferenceFromUrl(downloadURL);

    Uri contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
    String type = "";
    String mime = "";
    String folderName = "";

    if (downloadURL.contains("jpg") || downloadURL.contains("jpeg")
            || downloadURL.contains("png") || downloadURL.contains("webp")
            || downloadURL.contains("tiff") || downloadURL.contains("tif")) {
        type = ".jpg";
        mime = "image/*";
        contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
        folderName = Environment.DIRECTORY_PICTURES;
    }
    if (downloadURL.contains(".gif")){
        type = ".gif";
        mime = "image/*";
        contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
        folderName = Environment.DIRECTORY_PICTURES;
    }
    if (downloadURL.contains(".mp4") || downloadURL.contains(".avi")){
        type = ".mp4";
        mime = "video/*";
        contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
        folderName = Environment.DIRECTORY_MOVIES;
    }
    if (downloadURL.contains(".mp3")){
        type = ".mp3";
        mime = "audio/*";
        contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
        folderName = Environment.DIRECTORY_MUSIC;
    }

            final String relativeLocation = folderName + "/" + getString(R.string.app_name);

        final ContentValues contentValues = new ContentValues();
        contentValues.put(MediaStore.MediaColumns.DISPLAY_NAME, UUID.randomUUID().toString() + type);
        contentValues.put(MediaStore.MediaColumns.MIME_TYPE, mime); //Cannot be */*
        contentValues.put(MediaStore.MediaColumns.RELATIVE_PATH, relativeLocation);

        ContentResolver resolver = getContentResolver();
        Uri uriResolve = resolver.insert(contentUri, contentValues);

        try {

            if (uriResolve == null || uriResolve.getPath() == null) {
                throw new IOException("Failed to create new MediaStore record.");
            }

            stream = resolver.openOutputStream(uriResolve);

            //This is 1GB change this depending on you requirements
            httpsReference.getBytes(1024 * 1024 * 1024)
            .addOnSuccessListener(bytes -> {
                try {

                    int bytesRead;

                    inputStream = new ByteArrayInputStream(bytes);

                    while ((bytesRead = inputStream.read(bytes)) > 0) {
                        stream.write(bytes, 0, bytesRead);
                    }

                    inputStream.close();
                    stream.flush();
                    stream.close();
//FINISH

                } catch (IOException e) {
                    closeSession(resolver, uriResolve, e);
                    e.printStackTrace();
                    Crashlytics.logException(e);
                }
            });

        } catch (IOException e) {
            closeSession(resolver, uriResolve, e);
            e.printStackTrace();
            Crashlytics.logException(e);

        }