File length is 0 when recreating file from URI, or original filepath [getExternalFilesDir(String type) vs getFilesDir()]

Question

A little bit of background first: this app takes a picture and uploads to an Azure blob storage.

The picture is stored in a file (internal storage) using getA

Answer 1

Found a workaround. This is the function I was using to get the file that was being passed to the Camera intent.

    // Create a File object for storing the photo
    private File createImageFile() throws IOException {
        // Create an image file name
        String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
        String imageFileName = "JPEG_" + timeStamp + "_";
        File storageDir = getApplicationContext().getFilesDir();

    mPhotoFileExists = true;

    // check if access to external storage exists
    // if returned true, return the new file
    // if returned false, user could have been requested for access
    // so, need to check if permission is available now
    // if still not available, return null

    if(haveWritePermissions())
        return File.createTempFile(
                imageFileName,  /* prefix */
                ".jpg",         /* suffix */
                storageDir      /* directory */
        );
    return null;
    }

I changed the storageDir from getApplicationContext().getFilesDir(); to getApplicationContext.getExternalFilesDir(null);

Docs: getExternalFilesDir(String type), getFilesDir()

I passed null since I didn't want to put Environment.DIRECTORY_PICTURES, which would allow the Media Scanner to find the image file.

I understand that this, in no way, is a 'fix'. Still looking for an answer as to why getFilesDir() is causing this issue.

EDIT: Very pressing reason as to why this is not a good solution - external storage may not always be available, and there would not be any workaround in that case. Also, any other app with permission WRITE_EXTERNAL_STORAGE can write here. So, no security is enforced either.