// drawerToggle creates the hamburger icon at the start of the AppBar.
drawerToggle = new ActionBarDrawerToggle(this, drawerLayout, supportAppBar, R.string.open_navigation, R.string.close_navigation);
// drawerToggle creates the hamburger icon at the start of the AppBar.
drawerToggle = new ActionBarDrawerToggle(this, drawerLayout, supportAppBar, R.string.open_navigation, R.string.close_navigation);