Swift – 在App Delegate中实例化没有故事板的导航控制器

我正在重build一个没有故事板的应用程序，而我遇到的最麻烦的部分是以编程方式导航到视图。 很less有东西写在那里不使用故事板，所以find答案是艰难的。

我的问题很简单。 我有我的ViewController和我的SecondViewController ，我想从前者推到后者。

在AppDelegate ：

 func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool { // Override point for customization after application launch. window = UIWindow(frame: UIScreen.mainScreen().bounds) window?.backgroundColor = UIColor.whiteColor() window?.rootViewController = ViewController() window?.makeKeyAndVisible() return true } 

然后在ViewController.swift ：

 class ViewController: UIViewController, AVAudioPlayerDelegate, UITextFieldDelegate { override func viewDidLoad() { super.viewDidLoad() startFinishButton.setTitle("Begin", forState: .Normal) startFinishButton.addTarget(self, action: "moveToSecondViewController", forControlEvents: .TouchUpInside) view.addSubview <*> startFinishButton } func moveToSecondViewController(sender: UIButton) { let vc = SecondViewController() println(self.navigationController) // returns nil self.navigationController?.pushViewController(vc, animated: true) } } 

打印self.navigationController返回nil。 我试过了：

var navController = UINavigationController()当ViewController类被创build（但在ViewDidLoad之外，正好在类声明下）并且使用navController var进行了推送，但是没有工作。

我想也许解决的办法是在App Delegate中创build一个导航控制器，整个应用程序将使用，我想作为一个全局variables？

我希望这篇文章可以服务于许多其他Swift新手，并希望从应用程序中删除故事板。

感谢您的帮助。

Answer 1

在Swift 3

将此代码放在AppDelegate类的didFinishLaunchingWithOptions方法内。

 window = UIWindow(frame: UIScreen.main.bounds) let mainController = MainViewController() as UIViewController let navigationController = UINavigationController(rootViewController: mainController) navigationController.navigationBar.isTranslucent = false self.window?.rootViewController = navigationController self.window?.makeKeyAndVisible() 

Answer 2

在AppDelegate中

 var window: UIWindow? var navController: UINavigationController? func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool { navController = UINavigationController() var viewController: ViewController = ViewController() self.navController!.pushViewController(viewController, animated: false) self.window = UIWindow(frame: UIScreen.mainScreen().bounds) self.window!.rootViewController = navController self.window!.backgroundColor = UIColor.whiteColor() self.window!.makeKeyAndVisible() return true } 

在ViewController中

 class ViewController: UIViewController { override func viewDidLoad() { super.viewDidLoad() self.title = "FirstVC" var startFinishButton = UIButton.buttonWithType(UIButtonType.System) as! UIButton startFinishButton.frame = CGRectMake(100, 100, 100, 50) startFinishButton.backgroundColor = UIColor.greenColor() startFinishButton.setTitle("Test Button", forState: UIControlState.Normal) startFinishButton.addTarget(self, action: "buttonAction:", forControlEvents: UIControlEvents.TouchUpInside) self.view.addSubview(startFinishButton) } func buttonAction(sender:UIButton!) { println("Button tapped") let vc = SecondViewController() self.navigationController?.pushViewController(vc, animated: true) } override func didReceiveMemoryWarning() { super.didReceiveMemoryWarning() // Dispose of any resources that can be recreated. } }