我可以显示全屏 ViewController，但仍然可以向下滑动以返回父（启动器）ViewController

在 iOS 13 中，当我们呈现一个新的 ViewController 时

         let newVC = NewViewController()
         self.present(newVC, animated: true)

它如下所示，但不是全屏，可以向下滑动以移回启动的 ViewController

要使其全屏显示，我们可以使用.fullScreen如下所示。

         let newVC = NewViewController()
         newVC.modalPresentationStyle = .fullScreen
         self.present(newVC, animated: true)

它将如下所示，全屏显示。但是，它不允许我再向下滑动以返回父级。

有没有办法在全屏打开的情况下向后滑动并返回父级？

您可以尝试以下示例：

class ViewController: UIViewController {
    
    override func viewDidLoad() {
        super.viewDidLoad()
    }

    //Button is added via storyboard
    @IBAction func presentButtonDidTap(_ sender: UIButton) {
        let vc = NewViewController()
        vc.modalPresentationStyle = .fullScreen
        present(vc, animated: true)
    }
}

class NewViewController: UIViewController {
    
    override func viewDidLoad() {
        self.view.backgroundColor = .gray
        
        let gesture = UISwipeGestureRecognizer(target: self, action: #selector(dismissVC))
        gesture.direction = .down
        view.isUserInteractionEnabled = true // For UIImageView
        view.addGestureRecognizer(gesture)
    }
    
    @objc
    private func dismissVC() {
        dismiss(animated: true)
    }
}