我如何傳遞一個控制器的功能

Question

你好，我有我已經宣佈AlertViewFunction這樣

func displayAlertMessage(userMessage: String,//controller){ 
    let myAlert = UIAlertController(title: "Alert", message: userMessage, preferredStyle: UIAlertControllerStyle.Alert); 
    let okAction = UIAlertAction(title: "Ok", style: UIAlertActionStyle.Default, handler: nil) 
    myAlert.addAction(okAction); 
    self.presentViewController(myAlert, animated: true, completion: nil)  
} 

的問題是一個工具類，我不能使用self這裏

self.presentViewController(myAlert, animated: true, completion: nil) 

我想通過一個控制器到這個功能，所以我可以這樣使用

controller.presentViewController(myAlert, animated: true, completion: nil) 

如何通過控制器來自任何ViewController。比方說，如果我在LoginViewController

Utility().displayAlertMessage(Message.INTERNETISNOTCONNECTED,//controller) 

Answer 1

Utility().displayAlertMessage(Message.INTERNETISNOTCONNECTED, controller: self) 

和

func displayAlertMessage(userMessage: String, controller: UIViewController) 
{ 
    controller?.presentViewController(myAlert, animated: true, completion: nil) 
} 

Answer 2

通在視圖控制器作爲參數傳遞給函數。

func displayAlertMessage(controller: UIViewController, title: String, message: String?) { 
    let alert = UIAlertController(title: title, message: message, preferredStyle: .Alert) 
    let okAction = UIAlertAction(title: "Ok", style: .Default, handler: nil) 
    alert.addAction(okAction) 
    controller.presentViewController(alert, animated: false, completion: nil) 
} 

或者你甚至可以提醒說返回進一步定製函數的調用者：

func displayAlertMessage(title: String, message: String?) -> UIAlertController { 
    let alert = UIAlertController(title: title, message: message, preferredStyle: .Alert) 
    let okAction = UIAlertAction(title: "Ok", style: .Default, handler: nil) 
    alert.addAction(okAction) 
    return alert 
} 

class controller: UIViewController { 
    override func viewDidLoad() { 
    super.viewDidLoad() 
    let alert = displayAlertMessage("title", message: nil) 
    presentViewController(alert, animated: true, completion: nil) 
    } 
}