无法以编程方式在Swift中创建UIViewController

Question

当我尝试创建一个UIViewControllerin 的实例时Swift,即使我没有在视图控制器中定义任何指定的inits(或其他任何东西,FWIW),所有继承的初始化器都不可用.

此外,如果我尝试通过使其成为根视图控制器来显示它,它永远不会显示:

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        // Override point for customization after application launch.

        window = UIWindow(frame: UIScreen.mainScreen().bounds)
        window?.makeKeyAndVisible()
        window?.backgroundColor = UIColor.greenColor()



        let vc = ImageViewController()
        window?.rootViewController = vc

        return true
    }

视图控制器的代码只是Xcode的模板:

import UIKit

class ImageViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


    /*
    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        // Get the new view controller using segue.destinationViewController.
        // Pass the selected object to the new view controller.
    }
    */

}

谁知道发生了什么？

Answer 1

正如您所指出的:只要nib名称与objective-C中的类名匹配,即使在初始化视图控制器时未指定nib名称,视图控制器仍将查找名称为nib的文件匹配视图控制器类的名称.

但由于某种原因(也许这是一个错误),Swift的情况并非如此.

而不是写:

let vc = ImageViewController()

初始化视图控制器时必须显式指定接口:

let vc = ImageViewController(nibName: "nibName", bundle: nil)