import UIKit

@UIApplicationMain

class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

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

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

        // Override point for customization after application launch.

        self.window!.backgroundColor = UIColor.whiteColor()

        self.window!.rootViewController = RootViewController()

        self.window!.makeKeyAndVisible()

        return true

    }

}

import UIKit

class RootViewController: UIViewController {

    override func viewDidLoad() {

        super.viewDidLoad()

        //初始化button

        let btn = UIButton(type: UIButtonType.Custom)

        //尺寸

        btn.frame = CGRect(x: , y: , width: , height: )

        //背景颜色

        btn.backgroundColor = UIColor.redColor()

        //设置标题

        btn.setTitle("按钮", forState: UIControlState.Normal)

        //设置标题的颜色

        btn.setTitleColor(UIColor.greenColor(), forState: UIControlState.Normal)

        //添加点击事件

        btn.addTarget(self, action: "printSomeThing:", forControlEvents: UIControlEvents.TouchUpInside)

        //self.view加载子视图btn

        self.view.addSubview(btn)

    }

    //点击按钮执行的方法

    func printSomeThing(button:UIButton){

        print(button)

    }

}