How to get select multiple image and upload to server using retrofit?

Question

I am trying to get selected images from user and upload it to backend. I tried getting path of selected images then reading it with file and then parsing it to multipart. I am getting only null values from getRealPathFromURI method. Is there any other way to do this or what wrong i am doing?

 ActivityResultLauncher<Intent> activityResultLauncher=registerForActivityResult(new ActivityResultContracts.StartActivityForResult(), new ActivityResultCallback<ActivityResult>() {
            @Override
            public void onActivityResult(ActivityResult result) {
                if(result.getResultCode()== Activity.RESULT_OK){
                    imageURI=new ArrayList<>();
                    Intent data=result.getData();
                    ClipData mClipData = data.getClipData();
                    int count = data.getClipData().getItemCount();
                    for (int i = 0; i < count; i++) {
                        Uri imageurl = data.getClipData().getItemAt(i).getUri();
                        imageURI.add(imageurl);
                    }
                    
                }else {
                    Toast.makeText(getApplicationContext(), "Some error occured", Toast.LENGTH_SHORT).show();
                }
            }
        });

btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent();
                intent.setType("image/*");
                intent.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, true);
                intent.setAction(Intent.ACTION_GET_CONTENT);
                activityResultLauncher.launch(Intent.createChooser(intent,"choose image"));
            }
        });

 MultipartBody.Builder builder = new MultipartBody.Builder();
 builder.setType(MultipartBody.FORM);

for (int i = 0; i < imageURI.size(); i++) {
            Uri uri=imageURI.get(i);
            String path=getRealPathFromURI(uri);  // here I am getting only null values
            File file=new File(path);
            builder.addFormDataPart("files[]",file.getName(), RequestBody.create(MediaType.parse("multipart/form-data"), file));
        }

private String getRealPathFromURI(Uri contentURI) {
        String result;
        Cursor cursor = getContentResolver().query(contentURI, null, null, null, null);
        if (cursor == null) { // Source is Dropbox or other similar local file path
            result = contentURI.getPath();
        } else {
            cursor.moveToFirst();
            int idx = cursor.getColumnIndex(MediaStore.Images.ImageColumns.DATA);
            result = cursor.getString(idx);
            cursor.close();
        }
        return result;
    }