SWIFT 闭包的简单使用二

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()
        //调用processData函数
        processData { () -> Int in
            print("回调")
            return 20
        }
    }
    /**
     * 闭包返回整型数据
     */
    func processData(printSomething:()->Int){
        print("执行操作")
        //执行闭包回调
        let num = printSomething()
        print("闭包返回值num:\(num)")
    }

}