SwiftUI通过监听小键盘高度添加背景，通过点击背景隐藏小键盘

效果图

ExtensionAfterNavigationBackHidden.swift

extension UINavigationController: UIGestureRecognizerDelegate {
    override open func viewDidLoad() {
        super.viewDidLoad()
        interactivePopGestureRecognizer?.delegate = self
    }

    public func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
        return viewControllers.count > 1
    }
}