Black background behind panned images. Swift 3

Question

class PhotoViewController: UIViewController {

override var prefersStatusBarHidden: Bool {
    return true
}

private var backgroundImage: UIImage

init(image: UIImage) {
    self.backgroundImage = image
    super.init(nibName: nil, bundle: nil)
    print(image)
}

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

override func viewDidLoad() {
    super.viewDidLoad()






    self.view.backgroundColor = UIColor.gray
    let backgroundImageView = UIImageView(frame: view.frame)
    backgroundImageView.image = backgroundImage
    view.addSubview(backgroundImageView)




    let panGestureRecognizer = UIPanGestureRecognizer(target: self, action: #selector(panGestureRecognizerAction(_:)))
    self.view.addGestureRecognizer(panGestureRecognizer)

    let cancelButton = UIButton(frame: CGRect(x: 10.0, y: 10.0, width: 20.0, height: 20.0))
    cancelButton.setImage(#imageLiteral(resourceName: "cancel"), for: UIControlState())
    cancelButton.addTarget(self, action: #selector(cancel), for: .touchUpInside)
    let next = UIButton(frame: CGRect(x: (view.frame.width)-90, y: (view.frame.height)-125, width: 70, height: 70))
    next.setImage(#imageLiteral(resourceName: "Next"), for: UIControlState())
    next.addTarget(self, action: #selector(cancel), for: .touchUpInside)
    view.addSubview(next)
    view.addSubview(cancelButton)
}




func panGestureRecognizerAction(_ gesture: UIPanGestureRecognizer){
    let translation = gesture.translation(in: view)
    view.frame.origin.y = translation.y

    if gesture.state == .ended{

        if view.frame.origin.y > 100 && view.frame.origin.y < 200{
            UIView.animate(withDuration: 0.5, animations: { 

                dismiss(animated: false, completion: nil)

            })
        } else{
            UIView.animate(withDuration: 0.3, animations: { 

                self.view.frame.origin = CGPoint(x: 0, y: 0)
            })
        }
    }
}

When I pan up or down and drag the image view down the background is black eventhough i specified it to be gray. How can the background be of my chosen color. If any more required info is needed to answer the question please let me know

Answer 1

看起来您的panGestureRecognizerAction正在移动视图，而不是backgroundImageView