swift-导航栏和tabbar(系统自带)

1,在AppDelegate.swift里面(下面这个函数里面写)

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {

//定义三个视图

　　　var oneview = Oneview()

var twoview = Twoview()

var threeview = ThreeView()

//导航栏

var threenav : UINavigationController = UINavigationController(rootViewController: threeview)

var oneNav :UINavigationController = UINavigationController(rootViewController: oneview)

var twoNav :UINavigationController = UINavigationController(rootViewController: twoview)

//tabbar

var oneItem :UITabBarItem = UITabBarItem(tabBarSystemItem: UITabBarSystemItem.Bookmarks, tag: 0)

var twoItem :UITabBarItem = UITabBarItem(tabBarSystemItem: UITabBarSystemItem.Downloads, tag: 1)

var treeItem :UITabBarItem = UITabBarItem(tabBarSystemItem: UITabBarSystemItem.Favorites, tag: 2)

oneview.tabBarItem = oneItem

twoview.tabBarItem = twoItem

threeview.tabBarItem = treeItem

　　　　var tc = UITabBarController()

tc.tabBar.barTintColor = UIColor.blackColor()

tc.viewControllers = [oneNav,twoNav,threenav]

self.window?.rootViewController = tc;

　　return true

}