Swift 2.2 协议和代理

import UIKit

// 协议的创建
protocol youname{    
    func younameis(name:NSString) -> Void
}
class ProfileViewController: UIViewController{
    
   // 声明一个协议类型的代理变量
    var delegate:youname!

    // 这个方法写在这里只是为了在后面的界面设置了代理之后，去调用这个方法。
    func delegatetest() -> Void {
        
        self.delegate.younameis("caoxiaocaoxiangni")
    }
   // 这里的思路其实和我们OC写的思路是一样的！
 
    override func viewDidLoad() {
        super.viewDidLoad()
        self.view.backgroundColor=UIColor.whiteColor()
    }
  
    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.
    }
    */
}

import UIKit

class MEViewController: UIViewController,youname {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        // Do any additional setup after loading the view.
        
        // 创建了变量，设置代理，遵守协议，调用方法。
        let you : ProfileViewController = ProfileViewController()
        you.delegate=self
        you.delegatetest()
        
    }
    // 上个控制器里面  delegatetest 这个方法中，我们又设置了让它的代理（其实就是MEViewController）调用 younameis 方法，前面界面的参数 caoxiaocao 也就传了过来！

    func younameis(name: NSString) {
     
           print(name) // caoxiaocao
    }
    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.
    }
    */
}