今天我們要來介紹tabbar，首先我們要到檔案中新增一個TabBarViewController，
預設的tabbar是在底下的所以我們沒辦法移動他的位子，所以我們設定我們需要的東西

   private func setupTabs() {
        let wordtime = createNav(whit: "世界時間", and: UIImage(systemName: "house"), vc: 世界時間())
        
        let home = createNav(whit: "鬧鐘", and: UIImage(systemName: "house"), vc: 鬧鐘())
        
        let seconds = createNav(whit: "碼表", and: UIImage(systemName: "house"), vc: 碼表())
      
        let timepiece = createNav(whit: "計時器", and: UIImage(systemName: "house"), vc: 計時器())
        
        self.setViewControllers([wordtime,home,seconds,timepiece], animated: true)

    }

  private func createNav(whit title: String, and image:UIImage?, vc:UIViewController) -> UINavigationController {
         let nav = UINavigationController(rootViewController: vc)
        nav.tabBarItem.title = title
        nav.tabBarItem.image = image
        return nav
        
    }

加上我們這兩行外我們要到SceneDelegate裡加上讓我們一開始就加載tabbar

       let window = UIWindow(windowScene: windowScene)
        window.rootViewController = TabBarViewController()
        self.window = window
        self.window?.makeKeyAndVisible()

我們這樣就可以正常顯示tabbar摟