I'm trying to use expansion files and I found an issue that I'm not able to resolve.
It seems that you can access the
File f = new File(Environment.getExternalStorageDirectory(), "Android/obb/my.package.name");
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
OP dropped the Target SDK to 22 and was able to avoid Dangerous permission work flow which was causing the issue.