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在另一个类(scene.swift)中引用我的视图控制器-所有变量都变为null?Swift 3

touchesbegan scene viewcontroller swift ios
  •  2
  • Liam  · 技术社区  · 6 年前

    我正在尝试从场景中的视图控制器调用一个方法。swift类-我能做到这一点。当我单击在我的视图控制器中设置的SKLabel节点时,在调用ToucheSbegind方法之后调用该方法。

    问题是,当我单击SKLabelNode时,控件会传递到场景。swift类和touchesbented方法中,我要调用的方法被调用,因此控件被传递回视图控制器,当我回到这里时,我的所有变量似乎都被设置为nil,好像它是控制器的一个完全不同的实例?

    当我尝试在ArViewController中设置标签的文本属性时,checkIfValidTime方法中出现错误。-我用**突出显示了这些行。

    错误: 

    Fatal error: Unexpectedly found nil while unwrapping an Optional value

    如何引用视图控制器的同一实例,以便在场景中声明时不会重置变量。敏捷的 或者有没有一种方法可以在视图控制器中实现touchesbearth方法,这样就不必实例化ARViewController?

    我非常感谢在这件事上的任何帮助,因为我已经被困了一段时间了,而且我对iOS和swift应用程序设计还不熟悉。

    我试图将代码限制在解释此问题所需的范围内。 任何问题都可以问。谢谢

    ARViewController: 

        public var receivedCallback : Bool = false

    class ARViewController: UIViewController, ARSKViewDelegate, URLSessionDelegate {
        // MARK: - IBOutlets
        @IBOutlet weak var sceneView: ARSKView!
        @IBOutlet weak var guideLabel: UILabel!
        @IBOutlet weak var testLbl: UILabel!

 var scene : Scene?
        static var dateToUse : Date?
        var aRLocalDate : Date?

        var button: SKSpriteNode?

        override func viewDidLoad() {
            super.viewDidLoad()
        }

        override func viewDidAppear(_ animated: Bool) {
            super.viewDidAppear(animated)
            /*
             Start the view's AR session with a configuration that uses the rear camera,
             device position and orientation tracking, and plane detection..
             */
            let configuration = ARWorldTrackingConfiguration()

            guard ARWorldTrackingConfiguration.isSupported else {
                fatalError(""
                    ARKit is not available on this device."")
            }
            sceneView.session.run(configuration)
            sceneView.delegate = self
            if let scene = SKScene(fileNamed: "Scene"){
                self.scene = scene as! Scene
                sceneView.presentScene(self.scene)
            } else {
                print("Error: scene initalisation failed")
            }
            let overflow = ((aRLocalDate?.debugDescription.count)! - 11)
            let endIndex = aRLocalDate?.debugDescription.index((aRLocalDate?.debugDescription.endIndex)!, offsetBy: -overflow)
            if let truncatedDate = aRLocalDate?.debugDescription.substring(to: endIndex!){
                DateLabel.text = truncatedDate
            }  
        }

        **/// - Tag: PlaceARContent**
        func view(_ view : ARSKView, nodeFor anchor: ARAnchor) -> SKNode? {
            if self.Generated == false{
                self.guideLabel.alpha = 0
                parentNode = SKShapeNode(rectOf: CGSize(width: 400, height: 720))
                var count = 1;
                for time in timesArray {
                    **//add a SKSpriteNode and assign image to it**
                    **let labelNode : SKLabelNode = SKLabelNode(text: time)**
                    labelNode.name = "booklabel" + String(count)
                    labelNode.isUserInteractionEnabled = false;
                    parentNode?.addChild(labelNode)
                    posy -= 60
                    count += 1
                }
                parentNode?.alpha = 0.6
                self.Generated = true

                drawEventNodes()
                return parentNode
            }
            else {
                return nil
            }
        }

        //check if the booking is not in the past
        func checkIfValidTime(bookingTime: String, startDateTimeDate: Date) -> Bool {
            thisDate = ARViewController.dateToUse;
            let date = Date()
            let currentHour = Calendar.current.component(.hour, from: date)
            if (startDateTimeDate > date) {
                print("Start time is greater than the current date. = valid")
               **self.guideLabel.text = "Test"**
                return true;
            }
            else {
                print("Start time is not valid - before current time")
                **self.guideLabel.text = "Test"**
                return false;
            }
        }

        func doPost(bookingTime: String) {
            print("Start of post method")
            thisDate = ARViewController.dateToUse;
            roomToBook = globalVariables.roomDictionary[globalVariables.userString]!
            let name = globalVariables.userString;
            let date = Date()
            let dateFormatter = DateFormatter()
            dateFormatter.dateFormat = "yyyy-MM-dd"
            let displayName = globalVariables.userString
            let startDateStr = dateFormatter.string(from: thisDate!)
            let startHourString = bookingTime
            print("StartDateStr:", startDateStr)
            dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss"
            let startDateTimeString = "\(startDateStr)T\(startHourString)"
            let startDateTimeDate = dateFormatter.date(from: startDateTimeString)
            let endDateTimeDate = startDateTimeDate?.addingTimeInterval(3600)//3600 = 1 hour
            let endDateTimeString = dateFormatter.string(from: endDateTimeDate!)
            print("Start Date Time String", startDateTimeString)
            print("End date time string", endDateTimeString)
            print ("room to book: ",roomToBook)

            let valid = checkIfValidTime(bookingTime: bookingTime, startDateTimeDate: startDateTimeDate!)

            if (valid == true) {
                let jsonObject: [String: Any] =
                    [
                        "subject": "Booking",
                        "body":[
                            "contentType": "HTML",
                            "content": "Test Booking"
                        ],
                        "start":[
                            "dateTime": startDateTimeString,
                            "timeZone": "UTC"
                        ],
                        "end": [
                            "dateTime": endDateTimeString,
                            "timeZone": "UTC"
                        ],
                        "location":[
                            "displayName": displayName
                        ],
                        "attendees":[[
                            "emailAddress": [
                                "address": roomToBook,
                                "name": displayName
                            ],

                            "type": "required"
                            ]]
                ]

                //let valid = JSONSerialization.isValidJSONObject(jsonObject) // true
                let jsonData = try? JSONSerialization.data(withJSONObject: jsonObject)

                // create post request
                let url = URL(string: "https://graph.microsoft.com/v1.0/me/events")!

                var request = URLRequest(url: url)
                request.setValue("Bearer \(globalVariables.accessToken)", forHTTPHeaderField: "Authorization")
                request.setValue("application/json; charset=utf-8", forHTTPHeaderField: "Content-Type")
                request.setValue("application/json; charset=utf-8", forHTTPHeaderField: "Accept")        // the expected response is also JSON
                request.httpMethod = "POST"

                // insert json data to the request
                request.httpBody = jsonData

                let task = URLSession.shared.dataTask(with: request) { data, response, error in
                    guard let data = data, error == nil else {
                        print(error?.localizedDescription ?? "No data")
                        return
                    }
                    let responseJSON = try? JSONSerialization.jsonObject(with: data, options: [])
                    if let responseJSON = responseJSON as? [String: Any] {
                        print(responseJSON)
                    }
                }

                task.resume()
                print("Post Done")
                print("Refreshing now")
                //code to refresh?

            }
            else {
                print("Invalid booking time - it is in the past.")
            }
        }

    场景Swift: 

    class Scene : SKScene{
    var controller = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ARStoryBoard") as! ARViewController
   // var controller: ARViewController!
    var bookingTime : String?

    override func touchesBegan(_ touches: Set<UITouch>, with event : UIEvent?) {
       // var c =  self.view?.window?.rootViewController as! ARViewController;

        for touch in touches {
            let location = touch.location(in: self)
            let node : SKNode = self.atPoint(location)
            let name = node.name
            switch name {
            case "booklabel1"?:
                controller.doPost(bookingTime: "08:00:00")
            case "booklabel2"?:
                controller.doPost(bookingTime: "09:00:00")
            case "booklabel3"?:
                controller.doPost(bookingTime: "10:00:00")
            case "booklabel4"?:
                controller.doPost(bookingTime: "11:00:00")
            case "booklabel5"?:
                controller.doPost(bookingTime: "12:00:00")
            case "booklabel6"?:
                controller.doPost(bookingTime: "13:00:00")
            case "booklabel7"?:
                controller.doPost(bookingTime: "14:00:00")
            case "booklabel8"?:
                controller.doPost(bookingTime: "15:00:00")
            case "booklabel9"?:
                controller.doPost(bookingTime: "16:00:00")
            case "booklabel10"?:
                controller.doPost(bookingTime: "17:00:00")
            case "booklabel11"?:
                controller.doPost(bookingTime: "18:00:00")
            default:
                print ("No Specific Label Clicked")
            }
        }
    }

}
    2 回复  |  直到 6 年前
        1
  •  4
  •   Pranavan SP    3 年前

    试试这个。( 检查更新的编辑答案:强烈建议 )

    ARViewController:在类外创建实例 

    weak var arViewControllerInstance = ARViewController()

    确保ARViewController类内的初始化: 

     override func viewDidLoad() {
            super.viewDidLoad()
            arViewControllerInstance = self
        }

    现在可以调用场景。Swift使用: 

    arViewControllerInstance?.doPost(bookingTime: "08:00:00")

    已编辑:强烈建议

    上述方法简单,但强烈不建议用于最佳实践。请查看下面使用委托协议的实现。

    创建协议 

    protocol ScenceArViewControllerDelegate {
    func doPost(bookingTime: String)
}

    在ARViewController类中添加上述委托,如下所示。 

    class ARViewController: UIViewController, ScenceArViewControllerDelegate{
    func doPost(bookingTime: String){
       //Funcion body goes here
    }
}

    在场景类中创建一个委托变量,如下所示(Scene.swift) 

    class Scene: SKScene{
    weak var delegateARVC: ScenceArViewControllerDelegate?
}

    一旦你实现了这一切。现在您已声明 delegateARVC 变量来自 ARViewController 如下代码所示。(注意:您可以对set value使用依赖项注入,但下面只对set对象使用依赖项注入) 

    class ARViewController: UIViewController, ScenceArViewControllerDelegate{

        var scene: Scene?
 
        override func viewDidLoad() {
            super.viewDidLoad()
            scene = Scene()
            scene.delegateARVC = self
        }

        func doPost(bookingTime: String){
           //Funcion body goes here
        }
    }

    现在一切都好了。现在,场景类知道它与 ARViewController 通过调用的方法 doPost 使用 ScenceArViewControllerDelegate .

    你可以打电话 AARViewController 的 doPost公司 方法,如下所示。 

    guard let delegateARCAvailable = delegateARVC else { return }
delegateARCAvailable.doPost(bookingTime: "08:00:00")

    你可以随意申请。谢谢

        2
  •  1
  •   MichaelV    6 年前

    @Liam有“所有权链”。 “Own”是指负责使对象保持活动状态。示例库、读者和书籍。这本书有图书馆的印章,所以它有参考价值,但这本书肯定并没有自己的图书馆。读卡器也一样。但图书馆和读者都声称拥有这本书。若并没有人拿着书去读(声明所有权),那个么图书馆也会被毁——他们的书也会被毁。

    在Swift中,通过 strong 和 weak 参考文献。所有变量均为 坚强的 默认情况下。

    通常,您可以查看由app delegate或其他视图控制器(手动或使用情节提要)实例化的控制器。其他任何人都可以被视图控制器使用,并且可以了解viewcontroller,但不“拥有”它。所以变量必须声明为 虚弱的 . 注意不要拥有 虚弱的 ,所以它必须是可选的,并且可以在任何时候为空(如果用户向后导航),所以您必须使用额外的保护。

    总结如下:

    1: 将场景中的viewController声明为弱: 

    class Scene : SKScene{
    weak var controller: ARViewController?
    ....*
}

    2: 为场景提供视图控制器。可以在创建场景或设置场景时执行此操作。例如: 

     class ARViewController: UIViewController, ARSKViewDelegate, URLSessionDelegate {
 //...
 var scene : Scene? {
    didSet{
       //Optional: In case you can change scenes - remove view controller from old scene 
       oldValue?.controller = nil
       //Actually set view controller of any scene it "own"
       scene?.controller = self
    }
 }

    附言:还有一个修饰语“unowned”。但这是一种更先进的技术,可能会导致问题和崩溃。我建议你熟悉 虚弱的 . 习惯 guard 保持循环,然后继续。

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