Navigator/MaterialPageRoute Missing Arguments Error

I have a BUTTON ,here is some code:
1

and i got the error like this:

I've never met an error like this, but when i add the 'dynamic' like this:

Try to change your Code and implement this :

onPressed: () {
  Navigator.push(
    context,
    MaterialPageRoute(builder: (context) => Newfa()),
  );
}