iOS/Swift - Crazy Segue

Question

Я хочу сканировать код ISBN (идентификатор книги) для популяции вида раньше. Поэтому я перехожу к просмотру, откуда я пришел.

И сумасшедшая вещь произошла. Я вижу свое мнение и приложение, когда вернусь к представлению входа (начальное представление), автоматически войдите в систему как освобожденный (уже зарегистрированный) и остановится в таблицеView, где у вас есть кнопка добавления для добавления новой книги.

Я не понимаю, почему после моего BookVC мое приложение прыгает в исходный VC?

ScanBookViewController.swift:

class ScanBookViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate { 

    var book = Book() 

    var captureSession: AVCaptureSession! 
    var previewLayer: AVCaptureVideoPreviewLayer! 

    override func viewDidLoad() { 
     super.viewDidLoad() 

     view.backgroundColor = UIColor.blackColor() 
     captureSession = AVCaptureSession() 

     let videoCaptureDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo) 
     let videoInput: AVCaptureDeviceInput 

     do { 
      videoInput = try AVCaptureDeviceInput(device: videoCaptureDevice) 
     } catch { 
      return 
     } 

     guard captureSession.canAddInput(videoInput) else { 
      alertPopUp("Scanning not supported", message: "Your device does not support scanning a code from an item. Please use a device with a camera.") 
      captureSession = nil 
      return 
     } 
     captureSession.addInput(videoInput) 

     let metadataOutput = AVCaptureMetadataOutput() 

     guard captureSession.canAddOutput(metadataOutput) else { 
      alertPopUp("Scanning not supported", message: "Your device does not support scanning a code from an item. Please use a device with a camera.") 
      captureSession = nil 
      return 
     } 
     captureSession.addOutput(metadataOutput) 
     metadataOutput.setMetadataObjectsDelegate(self, queue: dispatch_get_main_queue()) 
     metadataOutput.metadataObjectTypes = [AVMetadataObjectTypeEAN8Code, AVMetadataObjectTypeEAN13Code] 

     previewLayer = AVCaptureVideoPreviewLayer(session: captureSession) 
     previewLayer.frame = view.layer.bounds 
     previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill 
     view.layer.addSublayer(previewLayer) 

     captureSession.startRunning() 
    } 

    func alertPopUp(title:String, message:String) { 
     let alert = UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.Alert) 
     alert.addAction(UIAlertAction(title: "OK", style: .Default, handler: { (action) -> Void in 
      self.dismissViewControllerAnimated(true, completion: nil) 
     })) 
     self.presentViewController(alert, animated: true, completion: nil) 
    } 

    override func viewWillAppear(animated: Bool) { 
     super.viewWillAppear(animated) 

     if (captureSession?.running == false) { 
      captureSession.startRunning() 
     } 
    } 

    override func viewWillDisappear(animated: Bool) { 
     super.viewWillDisappear(animated) 

     if (captureSession?.running == true) { 
      captureSession.stopRunning() 
     } 
    } 

    func captureOutput(captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [AnyObject]!, fromConnection connection: AVCaptureConnection!) { 
     captureSession.stopRunning() 

     if let metadataObject = metadataObjects.first { 
      let readableObject = metadataObject as! AVMetadataMachineReadableCodeObject 

      AudioServicesPlaySystemSound(SystemSoundID(kSystemSoundID_Vibrate)) 
      foundCode(readableObject.stringValue) 
     } 

     dismissViewControllerAnimated(true, completion: nil) 
    } 


    func foundCode(code: String) { 
     book.setISBN(code) 
     book.setTitle("Super Titre") 
     book.setAuthor("Gil Felot") 
     book.setCover(UIImage(named: "iu.png")!) 
     performSegueWithIdentifier("infoFinded", sender: nil) 
    } 

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) { 

     if segue.identifier == "infoFinded" { 
      let bookVC: BookViewController = segue.destinationViewController as! BookViewController 
      bookVC.book = book 
     } 
    } 

    override func prefersStatusBarHidden() -> Bool { 
     return true 
    } 

    override func supportedInterfaceOrientations() -> UIInterfaceOrientationMask { 
     return .Portrait 
    } 
} 

BookViewController.swift:

class BookViewController: UIViewController { 

    var book:Book! 

    @IBOutlet weak var bookImage: UIImageView! 
    @IBOutlet weak var bookTable: UITableView! 

    override func viewDidLoad() { 
     super.viewDidLoad() 
     if book == nil { 
      print("test segue") 
      performSegueWithIdentifier("scanCode", sender: nil) 
     } else { 
      bookImage.image = book.getCover() 
     } 

     // Do any additional setup after loading the view. 
    } 

    override func viewWillAppear(animated: Bool) { 
     super.viewWillAppear(animated) 

    } 

    override func didReceiveMemoryWarning() { 
     super.didReceiveMemoryWarning() 
     // Dispose of any resources that can be recreated. 
    } 


} 

Любая идея, потому что я даже не знаю, где смотреть!

Answer 1

Когда вы установили segue, вы выбрали show (aka push) или выбрали модальный? Стандартный способ обработки передаваемых данных - это делегирование. Создайте протокол и объявите делегата в ScanBookViewController. Затем установите BookViewController в качестве делегата. Вызовите метод делегата, как только вы сканируете книгу, затем нажмите или отпустите scanBookViewController.

protocol ScanBookDelegate{ 

    func didScanBook(scannedBook: Book) 
} 

class ScanBookViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate { 

    var book = Book() 
    var delegate: ScanBookDelegate? // create a new delegate instance 
    var captureSession: AVCaptureSession! 
    var previewLayer: AVCaptureVideoPreviewLayer! 

    override func viewDidLoad() { 
     super.viewDidLoad() 

     view.backgroundColor = UIColor.blackColor() 
     captureSession = AVCaptureSession() 

     let videoCaptureDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo) 
     let videoInput: AVCaptureDeviceInput 

     do { 
      videoInput = try AVCaptureDeviceInput(device: videoCaptureDevice) 
     } catch { 
      return 
     } 

     guard captureSession.canAddInput(videoInput) else { 
      alertPopUp("Scanning not supported", message: "Your device does not support scanning a code from an item. Please use a device with a camera.") 
      captureSession = nil 
      return 
     } 
     captureSession.addInput(videoInput) 

     let metadataOutput = AVCaptureMetadataOutput() 

     guard captureSession.canAddOutput(metadataOutput) else { 
      alertPopUp("Scanning not supported", message: "Your device does not support scanning a code from an item. Please use a device with a camera.") 
      captureSession = nil 
      return 
     } 
     captureSession.addOutput(metadataOutput) 
     metadataOutput.setMetadataObjectsDelegate(self, queue: dispatch_get_main_queue()) 
     metadataOutput.metadataObjectTypes = [AVMetadataObjectTypeEAN8Code, AVMetadataObjectTypeEAN13Code] 

     previewLayer = AVCaptureVideoPreviewLayer(session: captureSession) 
     previewLayer.frame = view.layer.bounds 
     previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill 
     view.layer.addSublayer(previewLayer) 

     captureSession.startRunning() 
    } 

    func alertPopUp(title:String, message:String) { 
     let alert = UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.Alert) 
     alert.addAction(UIAlertAction(title: "OK", style: .Default, handler: { (action) -> Void in 
      self.dismissViewControllerAnimated(true, completion: nil) 
     })) 
     self.presentViewController(alert, animated: true, completion: nil) 
    } 

    override func viewWillAppear(animated: Bool) { 
     super.viewWillAppear(animated) 

     if (captureSession?.running == false) { 
      captureSession.startRunning() 
     } 
    } 

    override func viewWillDisappear(animated: Bool) { 
     super.viewWillDisappear(animated) 

     if (captureSession?.running == true) { 
      captureSession.stopRunning() 
     } 
    } 

    func captureOutput(captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [AnyObject]!, fromConnection connection: AVCaptureConnection!) { 
     captureSession.stopRunning() 

     if let metadataObject = metadataObjects.first { 
      let readableObject = metadataObject as! AVMetadataMachineReadableCodeObject 

      AudioServicesPlaySystemSound(SystemSoundID(kSystemSoundID_Vibrate)) 
      foundCode(readableObject.stringValue) 
     } 

     dismissViewControllerAnimated(true, completion: nil) 
    } 


    func foundCode(code: String) { 
     book.setISBN(code) 
     book.setTitle("Super Titre") 
     book.setAuthor("Gil Felot") 
     book.setCover(UIImage(named: "iu.png")!) 
     self.delegate?.didScanBook(book) //Call the delegate method 
     self.navigationController?.popViewControllerAnimated(true) 
    } 

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) { 

     if segue.identifier == "infoFinded" { 
      let bookVC: BookViewController = segue.destinationViewController as! BookViewController 
      bookVC.book = book 
     } 
    } 

    override func prefersStatusBarHidden() -> Bool { 
     return true 
    } 

    override func supportedInterfaceOrientations() -> UIInterfaceOrientationMask { 
     return .Portrait 
    } 
} 

class BookViewController: UIViewController,ScanBookDelegate { 

    var book:Book! 

    @IBOutlet weak var bookImage: UIImageView! 
    @IBOutlet weak var bookTable: UITableView! 

    override func viewDidLoad() { 
     super.viewDidLoad() 
     if book == nil { 
      print("test segue") 
      performSegueWithIdentifier("scanCode", sender: nil) 
     } else { 
      bookImage.image = book.getCover() 
     } 

     // Do any additional setup after loading the view. 
    } 

    override func viewWillAppear(animated: Bool) { 
     super.viewWillAppear(animated) 

    } 
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) { //set book view controller as delegate to scan book view controller 
    if segue.destinationViewController is ScanBookViewController{ 
     let scanBookViewController:ScanBookViewController = segue.destinationViewController 
     scanBookViewController.delegate = self 
    } 
} 
    override func didReceiveMemoryWarning() { 
     super.didReceiveMemoryWarning() 
     // Dispose of any resources that can be recreated. 
    } 

    fun didScanBook(scannedBook:Book) //respond as delegate 
    { 
     self.book = scannedBook 
    } 



}