Swift 中 iOS 12 的 sheetPresentationController legacy（问题）

Question

我必须扩展对为目标 iOS 15 制作的 Cocoapod 的支持，并且将 UINavigationController 显示为底部模式，为 UIViewController 呈现

问题是 self.bottomController.sheetPresentationController 仅适用于 iOS 15，并且必须在目标 12.0 之前有效

如果我评论这一行：

if let sheet = self.bottomController.sheetPresentationController {
    sheet.detents = [.large()]
}

并为 iOS 12 目标编译成功，但模态的内容显示为全屏。

如何模仿或做一些事情来将内容（红色文本）显示为模态，如图所示？

我尝试在我的 Pod 中使用其他 Pod，但没有成功。谢谢！

Answer 1

sheetPresentationController 仅适用于 ios 15 及更高版本，对于以前的版本，您需要设置 .custom modalPresentationStyle

            controller.modalPresentationStyle = .pageSheet
            if #available(iOS 15.0, *) {

                if let sheet = controller.sheetPresentationController {
                    sheet.detents = [.medium()]
                }
                
            } else {
                
                controller.modalPresentationStyle = .custom
                controller.transitioningDelegate = self
            }
            self.present(controller, animated: true, completion: nil)

// MARK: - UIViewControllerTransitioningDelegate

extension CPPdfPreviewVC: UIViewControllerTransitioningDelegate {


func presentationController(forPresented presented: UIViewController, presenting: UIViewController?, source: UIViewController) -> UIPresentationController? {
    PresentationController(presentedViewController: presented, presenting: presenting)
    }
}

并按给定添加演示控制器

class PresentationController: UIPresentationController {

  let blurEffectView: UIVisualEffectView!
  var tapGestureRecognizer: UITapGestureRecognizer = UITapGestureRecognizer()
  
  override init(presentedViewController: UIViewController, presenting presentingViewController: UIViewController?) {
      let blurEffect = UIBlurEffect(style: .dark)
      blurEffectView = UIVisualEffectView(effect: blurEffect)
      super.init(presentedViewController: presentedViewController, presenting: presentingViewController)
      tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(dismissController))
      blurEffectView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
      self.blurEffectView.isUserInteractionEnabled = true
      self.blurEffectView.addGestureRecognizer(tapGestureRecognizer)
  }
  
  override var frameOfPresentedViewInContainerView: CGRect {
      CGRect(origin: CGPoint(x: 0, y: self.containerView!.frame.height * 0.4),
             size: CGSize(width: self.containerView!.frame.width, height: self.containerView!.frame.height *
              0.6))
  }

  override func presentationTransitionWillBegin() {
      self.blurEffectView.alpha = 0
      self.containerView?.addSubview(blurEffectView)
      self.presentedViewController.transitionCoordinator?.animate(alongsideTransition: { (UIViewControllerTransitionCoordinatorContext) in
          self.blurEffectView.alpha = 0.7
      }, completion: { (UIViewControllerTransitionCoordinatorContext) in })
  }
  
  override func dismissalTransitionWillBegin() {
      self.presentedViewController.transitionCoordinator?.animate(alongsideTransition: { (UIViewControllerTransitionCoordinatorContext) in
          self.blurEffectView.alpha = 0
      }, completion: { (UIViewControllerTransitionCoordinatorContext) in
          self.blurEffectView.removeFromSuperview()
      })
  }
  
  override func containerViewWillLayoutSubviews() {
      super.containerViewWillLayoutSubviews()
    presentedView!.roundCorners([.topLeft, .topRight], radius: 22)
  }

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

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

extension UIView {
  func roundCorners(_ corners: UIRectCorner, radius: CGFloat) {
      let path = UIBezierPath(roundedRect: bounds, byRoundingCorners: corners,
                              cornerRadii: CGSize(width: radius, height: radius))
      let mask = CAShapeLayer()
      mask.path = path.cgPath
      layer.mask = mask
  }
}