open the Drawer by clicking a button

[YitschakGlik]

I created the drawer in a class - DrawerManager like your recommendation,
in my app there is a menu button in every activity and its action is to open the drawer.

i tried to do it like this: in the class DrawerManager, after .build();
I add: result.openDrawer();
so when the menu btn is clicked its creating the drawer and open it.

-- there is a better way to do it?