有没有办法为 .fullscreen 模态呈现的视图控制器进行交互式模态解雇？

Question

我想启用交互式模式关闭，它会随着用户手指在全屏模式呈现的视图控制器上平移 .fullscreen。我已经看到在内置它的 .pageSheet 和 .formSheet 上这样做是相当微不足道的，但还没有看到全屏的清晰示例。我猜我需要在我的 vc 代码主体中添加一个平移手势，然后自己调整状态，但想知道是否有人知道到底需要做什么/是否有更简单的方法这样做的方法，因为 .fullscreen 案例

似乎要复杂得多

Answer 1

可以通过创建自定义 UIPresentationController 和 UIViewControllerTransitioningDelegate 来完成。假设我们有 TestViewController，我们想要呈现 SecondViewController，总 presentedHeight 为 1.0（全屏）。演示文稿将通过 @IBAction func buttonPressed 触发，并且可以通过向下拖动控制器来关闭（我们已经习惯了）。添加一些 backgroundEffect 以在用户向下滑动 SecondViewController 时逐渐改变（尤其是仅使用 0.6 的 presentedHeight 时）也很好。

首先我们定义了 OverlayViewController ，它将成为稍后呈现的 SecondViewController 的超类，并将包含 UIPanGestureRecognizer.

   class OverlayViewController: UIViewController {

   var hasSetPointOrigin = false
   var pointOrigin: CGPoint?
   var delegate: OverlayViewDelegate?

   override func viewDidLoad() {
    super.viewDidLoad()
    let panGesture = UIPanGestureRecognizer(target: self, action: #selector(panGestureRecognizerAction))
    view.addGestureRecognizer(panGesture)

   }

   override func viewDidLayoutSubviews() {
    if !hasSetPointOrigin {
     hasSetPointOrigin = true
     pointOrigin = self.view.frame.origin
    }
   }
   @objc func panGestureRecognizerAction(sender: UIPanGestureRecognizer) {
    let translation = sender.translation(in: view)

 // Not allowing the user to drag the view upward
 guard translation.y >= 0 else { return }
 let currentPosition = translation.y
 let originPos = self.pointOrigin
 delegate?.userDragged(draggedPercentage: translation.y/originPos!.y)

 // setting x as 0 because we don't want users to move the frame side ways!! Only want straight up or down
 view.frame.origin = CGPoint(x: 0, y: self.pointOrigin!.y + translation.y)

 if sender.state == .ended {
     let dragVelocity = sender.velocity(in: view)
     if dragVelocity.y >= 1100 {
         self.dismiss(animated: true, completion: nil)
     } else {
         // Set back to original position of the view controller
         UIView.animate(withDuration: 0.3) {
             self.view.frame.origin = self.pointOrigin ?? CGPoint(x: 0, y: 400)
             self.delegate?.animateBlurBack(seconds: 0.3)
         }
     }
   }
  }
 }

 protocol OverlayViewDelegate: AnyObject {
 func userDragged(draggedPercentage: CGFloat)
 func animateBlurBack(seconds: TimeInterval)
 }

接下来我们定义自定义PresentationController

   class PresentationController: UIPresentationController {

     private var backgroundEffectView: UIView?
     private var backgroundEffect: BackgroundEffect?
 private var viewHeight: CGFloat?
 private let maxDim:CGFloat = 0.6
 private var tapGestureRecognizer: UITapGestureRecognizer = UITapGestureRecognizer()

 convenience init(presentedViewController: UIViewController,
                  presenting presentingViewController: UIViewController?,
                  backgroundEffect: BackgroundEffect = .blur,
                  viewHeight: CGFloat = 0.6)
 {

     self.init(presentedViewController: presentedViewController, presenting: presentingViewController)

     self.backgroundEffect = backgroundEffect
     self.backgroundEffectView = returnCorrectEffectView(backgroundEffect)
     self.tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(dismissController))
     self.backgroundEffectView?.autoresizingMask = [.flexibleWidth, .flexibleHeight]
     self.backgroundEffectView?.isUserInteractionEnabled = true
     self.backgroundEffectView?.addGestureRecognizer(tapGestureRecognizer)
     self.viewHeight = viewHeight
 }

 private override init(presentedViewController: UIViewController, presenting presentingViewController: UIViewController?) {
     super.init(presentedViewController: presentedViewController, presenting: presentingViewController)
 }

 override var frameOfPresentedViewInContainerView: CGRect {
     CGRect(origin: CGPoint(x: 0, y: self.containerView!.frame.height * (1-viewHeight!)),
            size: CGSize(width: self.containerView!.frame.width, height: self.containerView!.frame.height *
                             viewHeight!))
 }

 override func presentationTransitionWillBegin() {
     self.backgroundEffectView?.alpha = 0
     self.containerView?.addSubview(backgroundEffectView!)
     self.presentedViewController.transitionCoordinator?.animate(alongsideTransition: { (UIViewControllerTransitionCoordinatorContext) in
         switch self.backgroundEffect! {
         case .blur:
             self.backgroundEffectView?.alpha = 1
         case .dim:
             self.backgroundEffectView?.alpha = self.maxDim
         case .none:
             self.backgroundEffectView?.alpha = 0
         }
     }, completion: { (UIViewControllerTransitionCoordinatorContext) in })
 }

 override func dismissalTransitionWillBegin() {
     self.presentedViewController.transitionCoordinator?.animate(alongsideTransition: { (UIViewControllerTransitionCoordinatorContext) in
         self.backgroundEffectView?.alpha = 0
     }, completion: { (UIViewControllerTransitionCoordinatorContext) in
         self.backgroundEffectView?.removeFromSuperview()
     })
 }

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

 override func containerViewDidLayoutSubviews() {
     super.containerViewDidLayoutSubviews()
     presentedView?.frame = frameOfPresentedViewInContainerView
     backgroundEffectView?.frame = containerView!.bounds
 }

 @objc func dismissController(){
     self.presentedViewController.dismiss(animated: true, completion: nil)
 }

 func graduallyChangeOpacity(withPercentage: CGFloat) {
     self.backgroundEffectView?.alpha = withPercentage
 }

 func returnCorrectEffectView(_ effect: BackgroundEffect) -> UIView {
     switch effect {

     case .blur:
         var blurEffect = UIBlurEffect(style: .dark)
         if self.traitCollection.userInterfaceStyle == .dark {
             blurEffect = UIBlurEffect(style: .light)
         }
         return UIVisualEffectView(effect: blurEffect)
     case .dim:
         var dimView = UIView()
         dimView.backgroundColor = .black
         if self.traitCollection.userInterfaceStyle == .dark {
             dimView.backgroundColor = .gray
         }
         dimView.alpha = maxDim
         return dimView
     case .none:
         let clearView = UIView()
         clearView.backgroundColor = .clear
         return clearView
     }
    }
   }

     extension PresentationController: OverlayViewDelegate {
     func userDragged(draggedPercentage: CGFloat) {
     graduallyChangeOpacity(withPercentage: 1-draggedPercentage)

     switch self.backgroundEffect! {
     case .blur:
         graduallyChangeOpacity(withPercentage: 1-draggedPercentage)
     case .dim:
         graduallyChangeOpacity(withPercentage: maxDim-draggedPercentage)
     case .none:
         self.backgroundEffectView?.alpha = 0
     }
 }

 func animateBlurBack(seconds: TimeInterval) {
     UIView.animate(withDuration: seconds) {
         switch self.backgroundEffect! {
         case .blur:
             self.backgroundEffectView?.alpha = 1
         case .dim:
             self.backgroundEffectView?.alpha = self.maxDim
         case .none:
             self.backgroundEffectView?.alpha = 0
         }

     }
   }
  }

   enum BackgroundEffect {
    case blur
    case dim
    case none
   }

创建 SecondViewController 子类 OverlayViewController:

 class SecondViewController: OverlayViewController {

 override func viewDidLoad() {
     super.viewDidLoad()
     self.view.backgroundColor = .blue
     // Do any additional setup after loading the view.
 }

 override func viewDidLayoutSubviews() {
     super.viewDidLayoutSubviews()
     addSlider()
 }

 func addSlider() {
     let sliderWidth:CGFloat = 100
     let centerOfScreen = self.view.frame.size.width / 2
     let rect = CGRect(x: centerOfScreen - sliderWidth/2, y: 80, width: sliderWidth, height: 10)
     let slider = UIView(frame: rect)
     slider.backgroundColor = .black
     self.view.addSubview(slider)
 }

添加 showOverlay() 将在 buttonPressed 之后触发的功能，并使您的呈现 UIViewController (TestViewController) 符合 UIViewControllerTransitioningDelegate :

 class TestViewController: UIViewController {

 override func viewDidLoad() {
     super.viewDidLoad()

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

 @IBAction func buttonPressed(_ sender: Any) {
     showOverlay()
 }

 func showOverlay() {
     let secondVC =  UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "secondVC") as! SecondViewController
     secondVC.modalPresentationStyle = .custom
     secondVC.transitioningDelegate = self
     self.present(secondVC, animated: true, completion: nil)
 }
}

 extension TestViewController: UIViewControllerTransitioningDelegate {
 func presentationController(forPresented presented: UIViewController,
                             presenting: UIViewController?,
                             source: UIViewController) -> UIPresentationController?
 {
     let presentedHeight: CGFloat = 1.0
     let controller = PresentationController(presentedViewController: presented,
                                             presenting: presenting,
                                             backgroundEffect: .dim,
                                             viewHeight: presentedHeight)

     if let vc = presented as? OverlayViewController {
         vc.delegate = controller
     }
     return controller
  }
 }

现在我们应该能够使用 showOverlay() 函数将 presentedHeight 设置为 1.0 和 .dim 背景效果来呈现 SecondViewController .我们可以忽略 SecondViewController 类似于另一个模态演示。

有没有办法为 .fullscreen 模态呈现的视图控制器进行交互式模态解雇？

Is there a way to have interactive modal dismissal for a .fullscreen modally presented view controller?

modal-dialog

ios

swift