How can I get menu item in NavigationView?

Answer 1

I think you should first get the menu like this:

navigationView.getMenu().findItem(R.id.login).setVisible(false);

The main aspect of this code is calling navigationView.getMenu() to get the menu from this you will have a reference of current inflated menu and call findViewById() and after that you can whatever you what.

For Group of item ex:-

...

and then you can control this using :-

navigationView.getMenu().setGroupVisible(R.id.group_1, true)