Casting to an indirect subclass

I have been playing around with the google drive api and am having a hard time understanding why I cannot cast Result to DriveFolder.DriveFolderResult. In the documentation DriveFolder.DriveFolderResult is a indirect known subclass of Result, but when I try casting Result to DriveFolder.DriveFolderResult I get the exception,

`java.lang.ClassCastException: com.google.android.gms.drive.internal.v$e cannot be cast to com.google.android.gms.drive.DriveApi$DriveIdResult`

Why is this happening? Since DriveFolder.DriveFolderResult is a indirect known subclass shouldn't I be able to cast it to 'Result'?

Also to help you guys I pasted some code down below. This is taken directly from here. Why would this code work? How can I implement the interface ResultCallback to give me back DriveFolder.DriveFolderResult? The best solution for me would be to have a class implement ResultCallback, have the method onResult return some object that has the method getStatus() and I then can cast it to any indirect subclass I want. Is this possible?

ResultCallback<DriveFolderResult> folderCreatedCallback = new
            ResultCallback<DriveFolderResult>() {
        @Override
        public void onResult(DriveFolderResult result) {
            if (!result.getStatus().isSuccess()) {
                showMessage("Error while trying to create the folder");
                return;
            }
            showMessage("Created a folder: " + result.getDriveFolder().getDriveId());
        }
    }