Swift: 你好, UIKit!

main.swift

import UIKit

UIApplicationMain(
Process.argc, Process.unsafeArgv,
NSStringFromClass(MainApp), NSStringFromClass(MainAppDelegate)
)

app.swift

MainApp

MainAppDelegate

import UIKit

class MainApp: UIApplication {
override func sendEvent(event: UIEvent) {
super.sendEvent(event)
}
}

class MainAppDelegate: UIResponder, UIApplicationDelegate {

var window: UIWindow?

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

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

self.window!.rootViewController = UIViewController()
self.window!.backgroundColor = UIColor.whiteColor()
self.window!.makeKeyAndVisible()

self.window!.AddSubview {
let label = UILabel(frame: self.window!.frame)
label.textAlignment = .Center
label.text = "你好, UIKit!"
return label
}

return true
}

}

extension UIView {
func AddSubview(subview: ()->UIView) {
self.addSubview(subview())
}
}