actions: <Widget>[
          IconButton(
            icon: Icon(Icons.lock_open, semanticLabel: "Logout",),

            onPressed: () async {
              // hapus shared prefs login
              final prefs = await SharedPreferences.getInstance();
              prefs.remove('login');
              // redirect page/route ke login
              Navigator.push(
                context,
                MaterialPageRoute(builder: (context) => Login()),
              );
            },
          ),
        ],