无法居中弹出框 Swift

Question

我正在尝试制作一个允许用户在图像之间滑动的弹出框（有没有比使用弹出框更好的方法？）。

现在为了制作弹出框，我花了几个小时在谷歌上搜索如何在屏幕上制作一个矩形中心。我的代码来自互联网：

    // get a reference to the view controller for the popover
    let popController = UIStoryboard(name: "Event", bundle: nil).instantiateViewController(withIdentifier: "carouselPopover")

    // set the presentation style
    popController.modalPresentationStyle = UIModalPresentationStyle.popover

    let width = view.frame.width
    popController.preferredContentSize = CGSize(width: width, height: 300)
    // set up the popover presentation controller
    popController.popoverPresentationController?.permittedArrowDirections = UIPopoverArrowDirection.up
    popController.popoverPresentationController?.delegate = self
    popController.popoverPresentationController?.sourceView = self.view
    popController.popoverPresentationController?.sourceRect = CGRect(x: view.bounds.midX, y: view.bounds.midY, width: 0, height: 0)
    popController.popoverPresentationController?.permittedArrowDirections = UIPopoverArrowDirection(rawValue: 0)

    // present the popover
    self.present(popController, animated: true, completion: nil)

但是，对于我的生活，我无法理解为什么弹出框没有居中

只有当我设置 popController 的首选内容大小时，它才会失去中心。有什么想法吗？

TL:DR 我想 1) 在屏幕上居中弹出框，2) 使弹出框的比例为 1:1，以及 3) 使弹出框的宽度与父屏幕的宽度成比例。如果没有 1000 行代码，我怎么能做到这一点。

Answer 1

您可以创建自定义弹出框类。然后你建立委托模式来确定用户是否滑动。

protocol PopoverDelegate: class {
  func imageviewDidSwipe(_ popover: Popover)
}

class Popover: UIView {

weak var delegate: PopoverDelegate?

  init(frame: CGRect) {
   super.init(frame: frame)
   backgroundColor = UIColor.white
  }

  func setupImage(_ image: UIImage) {
    let imageView = UIView(frame: CGRect.zero)
    imageView.image = image
    self.addSubview(imageView)

    imageView.translatesAutoresizingMaskIntoConstraints = false
    imageView.centerXAnchor.constraint(equalTo: centerXAnchor).isActive = true
    imageView.centerYAnchor.constraint(equalTo: centerYAnchor).isActive = true
    imageView.heightAnchor.constraint(equalToConstant: 50).isActive = true // However big you want
    imageView.widthAnchor.constraint(equalToConstant: 50).isActive = true // However big you want
  }

  func showPopover(over view: UIView) {
    view.addSubview(self)
    translatesAutoResizingMaskIntoConstraints = false
    centerXAnchor.contraint(equalTo: view.centerXAnchor).isActive = true
    centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
    heightAnchor.constraint(equalToConstant: frame.height).isActive = true
    widthAnchor.constraint(equalToConstant: frame.width).isActive = true
 }

}

使用...

class vC: UIViewController {

  func ImageOnClick() {
   // change view to where you want popover to show on top of
   let popover = Popover(frame: view.frame)
   popover.setupImage(image.png)
   popover.delegate = self
   showPopover(over: view)
  }

}

extension vC: PopoverDelegate {
  func imageviewDidSwipe(_ popover: Popover) {
    // image swiped
  }
}