废话不多 直接上代码

        self.window = UIWindow(frame: UIScreen.mainScreen().bounds)

        self.window!.backgroundColor = UIColor.whiteColor()

        let firstVC = OneViewController();//第一个标签对应的控制器

        let nav1=UINavigationController(rootViewController:firstVC);

        let image1=UIImage(named:"shenfen_icon");//标签对应的图片

        nav1.tabBarItem=UITabBarItem(title:"完美食材",image:image1,tag:1);

        let secondVC = TwoViewController();//第二个标签对应的控制器

        let nav2=UINavigationController(rootViewController:secondVC);

        let image2=UIImage(named:"shenfen_icon");

        nav2.tabBarItem=UITabBarItem(title:"国色天香",image:image2,tag:2);

　　nav2.tabBarItem.badgeValue = "2"        //设置该控制器对应的标签图片右上角显示的值

        let thirdVC = ThreeViewController();//第三个标签对应的控制器

        let nav3=UINavigationController(rootViewController:thirdVC);

        let image3=UIImage(named:"tanhao");

        nav3.tabBarItem=UITabBarItem(title:"实惠经典",image:image3,tag:3);

        let navArr=[nav1,nav2,nav3];

        let tabBarController = RootTabBarController()

        tabBarController.viewControllers=navArr; //把控制器交给tabbar

        tabBarController.tabBar.tintColor = UIColor.orangeColor() //tabbar标签和图片的颜色都会更改

　　//改变文字颜色
　　UITabBarItem.appearance().setTitleTextAttributes(
  　　  [NSForegroundColorAttributeName: UIColor.grayColor()], forState:.Normal)
　　UITabBarItem.appearance().setTitleTextAttributes(
   　　 [NSForegroundColorAttributeName: UIColor.orangeColor()], forState:.Selected)

 　　tabBarController.tabBarItem =  UITabBarItem(title: "QQ", image: UIImage(named: "qq_color"),

    selectedImage: UIImage(named: "qq_color")?.imageWithRenderingMode(.AlwaysOriginal))//原始的图片

        tabBarController.selectedIndex = 1//默认选中第几个控制器

        self.window!.rootViewController=tabBarController;//把tababr设置为根视图

         self.window!.makeKeyAndVisible()

        return true