修复Navigatoin测滑返回

class xxxxxViewController: UIViewController {  
      
    // 修复侧滑丢失  
    private var naDelegate: UIGestureRecognizerDelegate?  
  
  
    override func viewWillAppear(_ animated: Bool) {  
        super.viewWillAppear(animated)  
        // 修复侧滑丢失  
        naDelegate = navigationController?.interactivePopGestureRecognizer?.delegate  
        navigationController?.interactivePopGestureRecognizer?.delegate = self as? UIGestureRecognizerDelegate  
          
    }  
    override func viewWillDisappear(_ animated: Bool) {  
        super.viewWillDisappear(animated)  
  
        // 修复侧滑丢失  
        navigationController?.interactivePopGestureRecognizer?.delegate = naDelegate  
    }