When an Android activity is launched, it is launched with an intent and data. I call these the launch parameters. When it becomes necessary to retrieve these parameters, the code to do it is as follows:

        Intent launchIntent = getIntent();
        if (launchIntent != null) {
            Uri data = launchIntent.getData();
            if (data != null) {
                Filename = data.getPath(); // extracts the filename as /filepath/filename, if this is a file:///filepath/filename URI
           }
        }