在 GameScene (SpriteKit/Swift) 中显示 UIAlertController [英] Displaying a UIAlertController in GameScene (SpriteKit/Swift)

问题描述

快速显示 UIAlertView 的简单方法是:

The simple way to display a UIAlertView, in swift is:

let alert = UIAlertView()
alert.title = "Alert!"
alert.message = "A wise message"
alert.addButtonWithTitle("Ok, thank you")
alert.show()

但现在在 iOS 9 中已弃用，建议使用 UIAlertController:

But this is now depreciated in iOS 9 and recommends using UIAlertController:

let myAlert: UIAlertController = UIAlertController(title: "Alert!", message: "Oh! Fancy", preferredStyle: .Alert)
myAlert.addAction(UIAlertAction(title: "OK", style: .Default, handler: nil))
self.presentViewController(myAlert, animated: true, completion: nil)

这很好，但是我在使用 SpriteKit 并在 GameScene 中，这给出了一个错误 Value of type 'GameScene' has no member 'presentViewController'...

Which is great, but I'm using SpriteKit and inside a GameScene, which gives an error of Value of type 'GameScene' has no member 'presentViewController'...

我是否需要切换回我的 ViewController 来呈现这个，或者有没有办法从 GameScene 中调用它.

Do I need to switch back to my ViewController to present this or is there a way to call it from a GameScene.

我找到了 THIS 答案，但它是 Objective-C.

I found THIS answer, but it's Objective-C.

推荐答案

有很多方法可以处理这种情况，我不建议 Jozemite Apps 回答，因为这会导致具有多个视图控制器的应用程序出现问题.(你想要在当前视图控制器上显示警报，而不是根)

There are many ways to handle this situation, I do not recommend Jozemite Apps answer, because this will cause problems on apps with more than 1 view controller.(you want to present the alert on the current view controller, not the root)

我首选的方式是通过委托.需要做的是创建一个协议来处理消息:

My preferred way of doing it is through delegation. What needs to be done is create a protocol to handle messaging:

import Foundation
protocol ViewControllerDelegate
{
    func sendMessage(message:String);
}

在您的视图控制器中:

class ViewController : UIViewController, ViewControllerDelegate
{
    ...
    func sendMessage(message:String)
    {
       //do alert view code here
    }

    //in the view controllers view did load event
    func viewDidLoad()
    {
        var view = self.view as! GameSceneView
        view.delegate = self
    }

在你的视图代码中:

  var delegate : ViewControllerDelegate

终于在你要呈现的游戏场景中:

Finally in game scene where you want to present:

self.view.delegate?.sendMessage(message)

这种方式允许对 VC 进行有限访问，并且可以在需要时使用更多选项进行修改.

This way allows limited access to the VC, and can be modified with more options when needed.

另一种方法是设置一个通知系统，使用NSNotificationCenter将消息从场景传递到当前VC，并让它发送消息；

Another way is to set up a notification system, and use NSNotificationCenter to pass a message from the scene to the current VC and have it send a message;

在视图控制器中

func viewDidLoad()
{
  NSNotificationCenter.defaultCenter().addObserver(self,selector:"AlertMessage:",name:"AlertMessage",object:nil);

}

func AlertMessage(notification:NSNotification)
{
    if(let userInfo = notification.userInfo)
    {
      let message = userInfo["message"]
      ....//do alert view call here
    }
}

在游戏场景代码中:

...at the spot you want to send a message
let userInfo = ["message":message];
NSNotificationCenter.defaultCenter.postNotificationNamed("AlertMessage",object:nil,userInfo:userInfo)

另一种方法是将视图控制器指针保存到游戏场景视图:

Another approach is to save the view controller pointer to game scene view:

//in Game Scene View code
var viewController : UIViewController; 

//in the view controllers view did load event
func viewDidLoad()
{
    var view = self.view as! GameSceneView
    view.viewController = self
}

//finally in game scene where you want to present
let myAlert: UIAlertController = UIAlertController(title: "Alert!", message: "Oh! Fancy", preferredStyle: .Alert)
myAlert.addAction(UIAlertAction(title: "OK", style: .Default, handler: nil))
self.view.viewController.presentViewController(myAlert, animated: true, completion: nil)

另一种方法是使您的视图控制器全局化.

Yet another way is to make your view controller global.

在视图控制器代码中:私有变量 _instance : UIViewController

In view controller code: private var _instance : UIViewController

class ViewController : UIViewController
{
    class var instance
    {
        get
        {
            return _instance;
        }
    }

    func viewDidLoad()
    {
       _instance = self;
    }
}

然后调用

ViewController.instance!.  

当您需要访问您的视图控制器时.

whenever you need access to your view controller.

这些方法中的每一种都有优点和缺点，所以选择最适合你的方法.

Each of these methods have there strengths and weaknesses, so choose whatever way works best for you.

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