无法将后退按钮添加到 swift 导航 controller

Question

我有一个问题，我的应用程序有一个屏幕可以扫描 UPC 代码并在找到匹配项时显示产品详细信息屏幕，但是屏幕显示为模态并且没有后退按钮，它看起来像这样，如果我把它填满screen 你不能离开这个屏幕。

没有后退按钮的屏幕

这是通过搜索屏幕访问时的样子

这是带有后退按钮的外观

这是我在产品详细信息屏幕上使用的代码：

func launchApp(decodedURL: String) {
    
    if presentedViewController != nil {
        return
    }
    
    let decodedUPC = Int(decodedURL)
    
    guard let goodProduct = ProductsProvider().queryUPC(upcNumber: decodedUPC!) else  {
        
        let alertController = UIAlertController(title: "UPC Code not found \(String(describing: decodedUPC))", message: "We could not find this item, please use our search", preferredStyle: .alert)
        
        let confirmAction = UIAlertAction(title: "Ok", style: UIAlertAction.Style.default, handler: { (action) -> Void in
            
            // Code here
            self.dismiss(animated: true, completion: nil)
            
        })
        
        alertController.addAction(confirmAction)
        
        present(alertController, animated: true, completion: nil)
        return
        
    }
            

    let viewController:
        ProductDetailView = UIStoryboard(
            name: "Main", bundle: Bundle(for: ProductDetailView.self)
            ).instantiateViewController(withIdentifier: "productDetailViewController") as! ProductDetailView
    
    viewController.productDetail = goodProduct
    viewController.navigationItem.leftBarButtonItem = splitViewController?.displayModeButtonItem
    viewController.navigationItem.leftItemsSupplementBackButton = true
    
    
    let navigationController = UINavigationController(rootViewController: viewController)
    // navigationController.modalPresentationStyle = .fullScreen

    

    self.present(navigationController, animated: false, completion: nil)
    
}

任何帮助在屏幕上获得后退按钮的帮助将不胜感激

Answer 1

您可以使用 pushViewController 方法代替 present：

let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
let nextViewController = storyBoard.instantiateViewController(withIdentifier: "identifier_of_target_vc") as! ClassNameofTargetVC 
self.navigationController?.pushViewController(nextViewController, animated:true)

希望这可以帮助！

Answer 2

#方法一

来自关于pushViewController(_:animated:) 链接的 Apple 文档：

除了在堆栈顶部显示与新视图 controller 关联的视图外，此方法还相应地更新导航栏和工具栏。

要更新导航栏和工具栏以显示后退按钮，您应该从现有导航controller中推送 viewController：

self.navigationController?.pushViewController(viewController, animated: false)

代替：

let navigationController = UINavigationController(rootViewController: viewController)
self.present(navigationController, animated: false, completion: nil)

#方法二

要关闭全屏呈现的ViewController ，只需将UIBarButtonItem添加到 navigationItem：

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        title = "Presented View"

        navigationItem.leftBarButtonItem = UIBarButtonItem(barButtonSystemItem: .cancel, target: self, action: #selector(cancelAction))
    }

    @objc func cancelAction() {
        dismiss(animated: true)
    }
}