Flutter: Restricting screen capture in app

Question

I need to make sure the user is not able to capture screenshot of my flutter app in any screen. Is there any way to achieve this in Flutter by now?

I found the following snippet online but not sure where to put it, please help

onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_SECURE,
                WindowManager.LayoutParams.FLAG_SECURE);
}