快速關閉視圖時，屏幕不時凍結，沒有錯誤

Question

我遇到了一些麻煩：關閉ViewController在當前上下文中顯示圖片時，屏幕有時會凍結。

有人可以為我提供一些有關如何解決此問題的見解嗎？

我嘗試使用暫停按鈕檢查主線程，但未發現任何異常情況。

我的代碼示例如下：

import UIKit

class ViewControllerCell: UICollectionViewCell {

override init(frame: CGRect) {
    super.init(frame: frame)

    backgroundColor = UIColor.white

    addSubview(showPhotoButton)

    showPhotoButton.leftAnchor.constraint(equalTo: leftAnchor, constant: 200).isActive = true
    showPhotoButton.bottomAnchor.constraint(equalTo: topAnchor, constant: 160).isActive = true
    showPhotoButton.heightAnchor.constraint(equalToConstant: 50).isActive = true
    showPhotoButton.widthAnchor.constraint(equalToConstant: 70).isActive = true

}

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


lazy var showPhotoButton: UIButton = {
    let button = UIButton(type: .system)
    button.translatesAutoresizingMaskIntoConstraints = false
    button.setTitle("Show", for: .normal)
    button.addTarget(self, action: #selector(showSale), for: .touchUpInside)
    button.setTitleColor(UIColor(r: 120, g: 80, b: 255), for: .normal)
    return button
}()


@objc func showSale() {
    let popupViewController = SalePopupViewController()
    popupViewController.modalPresentationStyle = .overCurrentContext
    popupViewController.modalTransitionStyle = UIModalTransitionStyle.crossDissolve
    window!.rootViewController?.present(PopupViewController, animated: true, completion: nil)
    }

}

SalePopupViewController：

import UIKit

class SalePopupViewController: UIViewController {

override func viewDidLoad() {
    view.backgroundColor = UIColor(white: 1, alpha: 0.60)
    view.isOpaque = false

    view.addSubview(rebateImage)
    view.addSubview(dismissButton)

    dismissButton.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
    dismissButton.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
    dismissButton.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
    dismissButton.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true

    rebateImage.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
    rebateImage.centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: -35).isActive = true
    rebateImage.heightAnchor.constraint(equalToConstant: 290).isActive = true
    rebateImage.widthAnchor.constraint(equalTo: view.widthAnchor, multiplier: 1).isActive = true


}

let dismissButton: UIButton = {
    let button = UIButton(type: .system)
    button.addTarget(self, action: #selector(dismissPopup), for: .touchUpInside)
    button.translatesAutoresizingMaskIntoConstraints = false
    return button
}()

let rebateImage: UIImageView = {
    let image = UIImageView()
    image.translatesAutoresizingMaskIntoConstraints = false
    image.layer.masksToBounds = false
    image.layer.cornerRadius = 2
    image.contentMode = .scaleAspectFill
    image.clipsToBounds = true
    image.image = UIImage(named: "SaleCostco")
    return image
}()
@objc func dismissPopup() {
    weak var weakself = self

    weakself?.dismiss(animated: true, completion: { print("dismissing")})






       }

    }

}

Answer 1

第一件事是為什么要顯示來自window!.rootViewController?的彈出window!.rootViewController? 而不是您從中調用它的視圖控制器？ 只需使用present(PopupViewController, animated: true, completion: nil)代替。

第二件事是弱者自己的事情是完全沒有必要的，因為無法將自己從內存中釋放出來，但是您的關閉按鈕仍然存在，因此它可以牢固地引用自己，而弱者則完全沒有區別。

編輯

所以我沒有看到ViewControllerCell是一個集合視圖單元。 現在的解決方案有所不同：您有幾個選擇，1.在為indexPath函數的item編寫單元格時，將viewController引用傳遞給每個單元格

func collectionView(_ collectionView: UICollectionView, 
  cellForItemAt indexPath: IndexPath) -> UICollectionViewCell{
if let cell = collectionView.dequeueReusableCell(withIdentifier identifier: String) as? ViewControllerCell {
//do your thing here
 cell.parentViewController = self

}}

當然，您必須在collectionViewCell中設置一個公共變量

var parentViewController: UIViewController!
// you can also use the viewController subclass name that you created

//。 如果要使用特定功能。 如果只有禮物那么你就很好

最后，在呈現的地方使用parentViewController.present（....）