Ios 扩展UIViewController以显示UIAlertController而无需子类化

我希望重用代码，以便在我在几个my view控制器中删除tableview中的某些行时显示警报：

func confirmDeleteitem:字符串{

    let alert = UIAlertController(title: "Delete Planet", message: "Are you sure you want to permanently delete \(item)?", preferredStyle: .actionSheet)
     
    let deleteAction = UIAlertAction(title: "Delete", style: .destructive, handler: handleDeleteItem)
     
    let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: cancelDeleteItem)
    
    alert.addAction(deleteAction)
    alert.addAction(cancelAction)
    
    self.present(alert, animated: true, completion: nil)
}

func handleDeleteItem(alertAction: UIAlertAction!) -> Void {

    if let indexPath = deletePlanetIndexPath {
        presenter?.removePlanet(atIndex: indexPath, completion: { (result) in
            
            switch result {
            case .success(_):
                self.tableView.deleteRows(at: [indexPath], with: .fade)
                break
            case let .failure(error):
                print(error)
                break
            }
        })
        
        deletePlanetIndexPath = nil
    }
}


func cancelDeleteItem(alertAction: UIAlertAction!) {
    deletePlanetIndexPath = nil 
}

只有一个部分每次都会不同：

presenter?.removePlanet(atIndex: indexPath, completion: { (result) in
                
                switch result {
                case .success(_):
                    self.tableView.deleteRows(at: [indexPath], with: .fade)
                    break
                case let .failure(error):
                    print(error)
                    break
                }
            })

正如您所见，我可以简单地进行子类化并声明一些闭包变量，这些变量将在每次调用deleteAction时触发

---

这是一种非常简单的方法，但我对子类化并不是特别感兴趣。也许有一些关于完整扩展、基于协议的东西或任何其他建议的帮助。

您可以编写一个类扩展来查看控制器：

extension UIViewController {
    func createAlert(handleDeleteItem: @escaping () -> Void, cancelDeleteItem: @escaping  () -> Void) {
        let alert = UIAlertController(title: "Delete Planet", message: "Are you sure you want to permanently delete \(item)?", preferredStyle: .actionSheet)
     
        let deleteAction = UIAlertAction(title: "Delete", style: .destructive, handler: handleDeleteItem)
     
        let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: cancelDeleteItem)
    
        alert.addAction(deleteAction)
        alert.addAction(cancelAction)
    
        self.present(alert, animated: true, completion: nil)
    }
}

---

然后为每个不同的视图控制器传入适当的删除和取消函数。

您可以为视图控制器编写一个类扩展：

extension UIViewController {
    func createAlert(handleDeleteItem: @escaping () -> Void, cancelDeleteItem: @escaping  () -> Void) {
        let alert = UIAlertController(title: "Delete Planet", message: "Are you sure you want to permanently delete \(item)?", preferredStyle: .actionSheet)
     
        let deleteAction = UIAlertAction(title: "Delete", style: .destructive, handler: handleDeleteItem)
     
        let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: cancelDeleteItem)
    
        alert.addAction(deleteAction)
        alert.addAction(cancelAction)
    
        self.present(alert, animated: true, completion: nil)
    }
}

---

然后为每个不同的视图控制器传入适当的删除和取消功能。

UIAlertController的扩展可以工作：

class MyVC: UIViewController {
    private lazy var alertControllerA: UIAlertController = {
         return UIAlertController.customAlertController(/* params */)
    }()
}

private extension UIAlertController {
        static func customAlertController(_ item: String, handleDeleteItem: @escaping () -> Void, cancelDeleteItem: @escaping  () -> Void) -> UIAlertController {
            let alertController = UIAlertController(title: "Delete Planet", message: "Are you sure you want to permanently delete \(item)?", preferredStyle: .actionSheet)
         
        let deleteAction = UIAlertAction(title: "Delete", style: .destructive, handler: handleDeleteItem)
     
        let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: cancelDeleteItem)
    
        alert.addAction(deleteAction)
        alert.addAction(cancelAction)
    
        return alertController
    }
}

---

UIAlertController的扩展可以工作：

class MyVC: UIViewController {
    private lazy var alertControllerA: UIAlertController = {
         return UIAlertController.customAlertController(/* params */)
    }()
}

private extension UIAlertController {
        static func customAlertController(_ item: String, handleDeleteItem: @escaping () -> Void, cancelDeleteItem: @escaping  () -> Void) -> UIAlertController {
            let alertController = UIAlertController(title: "Delete Planet", message: "Are you sure you want to permanently delete \(item)?", preferredStyle: .actionSheet)
         
        let deleteAction = UIAlertAction(title: "Delete", style: .destructive, handler: handleDeleteItem)
     
        let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: cancelDeleteItem)
    
        alert.addAction(deleteAction)
        alert.addAction(cancelAction)
    
        return alertController
    }
}

---

感谢已经发布答案的人，非常感谢。我还提出了另一个解决方案。因此，如果我们使用Tob示例，我们将扩展所有UIViewController的功能，如果我们使用h和.h示例，我们将装饰我们的特定视图控制器，但这会迫使我们编写额外的惰性代码，这没什么大不了的，我主要喜欢这个示例这一示例不会使任何视图控制器能够使用UIAlerController扩展，但我将遵循基于协议的扩展解决方案：

导入UIKit

protocol UIAlertControllerManageable {
    func createAlert(with text: String, handleDeleteItem: @escaping (UIAlertAction) -> Void, cancelDeleteItem: @escaping  (UIAlertAction) -> Void)
}

extension UIAlertControllerManageable where Self: UIViewController {
   
    func createAlert(with text: String, handleDeleteItem: @escaping (UIAlertAction) -> Void, cancelDeleteItem: @escaping  (UIAlertAction) -> Void) {
        
        let alert = UIAlertController(title: "Delete", message: "Are you sure you want to permanently delete \(text)?", preferredStyle: .actionSheet)
         
        let deleteAction = UIAlertAction(title: "Delete", style: .destructive, handler: handleDeleteItem)
         
        let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: cancelDeleteItem)
        
        alert.addAction(deleteAction)
        alert.addAction(cancelAction)
        
        self.present(alert, animated: true, completion: nil)
    }
}

用法：

class HomeViewController: UIViewController, UIAlertControllerManageable {
        
        func confirmDelete(deleteText: String) {
            
            createAlert(with: deleteText) { (action) in
                
                if let indexPath = self.deleteItemIndexPath {
                    self.presenter?.removeItem(atIndex: indexPath, completion: { (result) in
                        
                        switch result {
                        case .success(_):
                            self.tableView.deleteRows(at: [indexPath], with: .fade)
                            break
                        case let .failure(error):
                            print(error)
                            break
                        }
                    })
                    
                    self.deleteItemIndexPath = nil
                }
                
            } cancelDeleteItem: { (action) in
                self.deleteItemIndexPath = nil
            }
        }
    
    }

---

让我知道你的想法，谢谢！

感谢那些已经发布答案的人，非常感谢。我还提出了另一个解决方案。因此，如果我们使用Tob示例，我们将扩展所有UIViewController的功能，如果我们使用h和.h示例，我们将装饰特定的视图控制器，但这会迫使我们使用I编写额外的惰性代码这没什么大不了的，我最喜欢这个示例，它没有使任何视图控制器能够使用UIAlerController扩展，但我将遵循一个基于协议的扩展解决方案：

导入UIKit

protocol UIAlertControllerManageable {
    func createAlert(with text: String, handleDeleteItem: @escaping (UIAlertAction) -> Void, cancelDeleteItem: @escaping  (UIAlertAction) -> Void)
}

extension UIAlertControllerManageable where Self: UIViewController {
   
    func createAlert(with text: String, handleDeleteItem: @escaping (UIAlertAction) -> Void, cancelDeleteItem: @escaping  (UIAlertAction) -> Void) {
        
        let alert = UIAlertController(title: "Delete", message: "Are you sure you want to permanently delete \(text)?", preferredStyle: .actionSheet)
         
        let deleteAction = UIAlertAction(title: "Delete", style: .destructive, handler: handleDeleteItem)
         
        let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: cancelDeleteItem)
        
        alert.addAction(deleteAction)
        alert.addAction(cancelAction)
        
        self.present(alert, animated: true, completion: nil)
    }
}

用法：

class HomeViewController: UIViewController, UIAlertControllerManageable {
        
        func confirmDelete(deleteText: String) {
            
            createAlert(with: deleteText) { (action) in
                
                if let indexPath = self.deleteItemIndexPath {
                    self.presenter?.removeItem(atIndex: indexPath, completion: { (result) in
                        
                        switch result {
                        case .success(_):
                            self.tableView.deleteRows(at: [indexPath], with: .fade)
                            break
                        case let .failure(error):
                            print(error)
                            break
                        }
                    })
                    
                    self.deleteItemIndexPath = nil
                }
                
            } cancelDeleteItem: { (action) in
                self.deleteItemIndexPath = nil
            }
        }
    
    }

---

让我知道你的想法，谢谢！

我高估了你的答案谢谢！我刚刚提出了另一个解决方案。我发布了答案我高估了你的答案谢谢！我刚刚提出了另一个解决方案。我发布了答案我也高估了你的答案谢谢！我提出了另一个解决方案。答案是postedI我也高估了你的答案谢谢！我想出了另一个解决方案。答案已发布