swift - 放松 Segue 不消除 View

Question

问题:

放松转场而不是关闭 View ，即使它有效。

场景:

我有一个“添加产品”屏幕，当添加产品时，我会启动 unwind segue，这又会显示一个弹出窗口:“已添加新产品”。

事实:1) 产品成功添加到数据库2)目标中unwind segue的@IBAction中显示弹出“产品已添加”，并且出现3) 弹出窗口“已添加产品”显示在 AddProductScreen View

上

图1:Unwind segue的存在

@IBAction 位于目标 View 中:

@IBAction func unwindFromAddProductViewSuccess(segue: UIStoryboardSegue)
    {
        AlertManager.showTimedAlert(title: "Success", message: "New Product added", timeShowing: 1, callingUIViewController: self)
    }

在AddProductView中调用函数来注册产品:

private func registerProductAndPerformSegue(productToRegister prod: Product)
    {
        self.registerProduct(prodToRegister: prod)
        Constants.logger.debug("New product registered")
        self.performSegue(withIdentifier: "unwind_from_add_product_success", sender: self)

    }

在“添加产品 View ”中，单击“确认”后，将显示一条警告“您确定吗？”然后系统会提示您单击"is"或“否”。

这是警报的代码:

AlertManager.ShowAlert(controllerToShowAlert: self, alertTitle: LocalizationStrings.Products.ADD_PRODUCT_TITLE, alertText: LocalizationStrings.Products.ADD_PRODUCT_CONFIRMATION,
                                           alertStyle: UIAlertControllerStyle.alert,
                                           leftButtonAction: UIAlertAction(title: LocalizationStrings.YES_TEXT, style: .default, handler:
                                            {
                                                (action: UIAlertAction!) in

                                                let user = Auth.auth().currentUser

                                                if let user = user
                                                {
                                                    let product : Product = Product(name: name!, price: Double(price!)!, currency: "USD", description: desc!,
                                                                                    location: "USA", ownerID: user.uid, ownerName: user.displayName!, uniqueID: "", mainImageURL: nil, category: category)


                                                    let storageRef = Storage.storage().reference().child(product.getUniqueID()).child("pic0.jpg")
                                                    if let mainChosenImage = self.selectedImageToUpload
                                                    {
                                                        Constants.logger.debug("Product picture chosen")
                                                        if let uploadData = UIImageJPEGRepresentation(mainChosenImage, 0.2)
                                                        {
                                                            storageRef.putData(uploadData, metadata: nil)
                                                            {
                                                                (StorageMetaData, error) in
                                                                if error != nil
                                                                {
                                                                    Constants.logger.error("Add Product: Couldn't store image in database!")
                                                                    return
                                                                }

                                                                self.mainImageURL = StorageMetaData?.downloadURL()?.absoluteString
                                                                if let urlString = self.mainImageURL
                                                                {
                                                                    product.AddImageURLToProduct(URL: urlString)
                                                                    self.registerProductAndPerformSegue(productToRegister: product)
                                                                }
                                                            }
                                                        }
                                                        else
                                                        {
                                                            Constants.logger.error("Couldn't convert uploaded image to UIImageJPEGRepresentation")
                                                        }
                                                    }
                                                    else
                                                    {
                                                        Constants.logger.debug("Product picture NOT chosen")
                                                        self.registerProductAndPerformSegue(productToRegister: product)
                                                    }
                                                }
                                           }),

                                           rightButtonAction: UIAlertAction(title: LocalizationStrings.NO_TEXT, style: .cancel, handler: { (action: UIAlertAction!) in
                                            print("Handle Cancel Logic here")
                                           }))

我在这里做错了什么？

Answer 1

如果没有有关 Storyboard设置和代码的更多详细信息，很难判断确切的问题是什么。但我假设您有两个 View Controller ，我将尝试引导您完成执行 unwindSegue 的步骤，您可以检查是否遗漏了某些内容。

假设您有两个 View Controller :FirstViewController 和AddProductViewController，并且AddProductViewController` 使用推送转场呈现。

在 FirstViewController 中你有:

@IBAction func unwindFromAddProductViewSuccess(segue: UIStoryboardSegue) {
    AlertManager.showTimedAlert(title: "Success", message: "New Product added", timeShowing: 1, callingUIViewController: self)
}

然后，将“保存”或“添加”按钮从 AddProductViewController 连接到 unwindFromAddProductViewSuccess: 操作方法。

您还可以将“保存”或“添加”按钮连接到 SecondViewController 来调试 segue 是否被调用:

class SecondViewController: UIViewController { 
    @IBOutlet weak var saveButton: UIBarButtonItem!

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        guard let uiBarButtonItem = sender as? UIBarButtonItem else {
            print("There is no UIBarButtonItem sender")
            return
        }

        if saveButton == uiBarButtonItem {
            print("save button tapped")
        }
        print("A segue with an identifier \(segue.identifier ?? "") was called.")
    }
}

假设您没有栏按钮项，并且想要手动调用 unwidnSegue，也许在用户点击 UIAlertController 操作后，那么您可以执行类似的操作这个:

@IBAction func orderButtonTapped(_ sender: UIButton) {
    let alert = UIAlertController(title: "Order Placed!", message: "Thank you for your order.\nWe'll ship it to you soon!", preferredStyle: .alert)
    let OKAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: {
    (_)in
        self.performSegue(withIdentifier: "unwindToMenu", sender: self)
    })

    alert.addAction(OKAction)
    self.present(alert, animated: true, completion: nil)
}

在某些情况下，您尝试展开的 UIViewController 位于 UINavigationController 堆栈的底部，在这种情况下，调用 unwindSegue 将不起作用任何事物。之前有一个类似的问题，here .

希望这些信息可以帮助您解决问题。