iOS 13.0 UIMenu和UIAction for UIContextMenuConfiguration

Question

我正在尝试使用iOS 13.0Beta中引入的新API。我下载了Xcode 11.0Beta 3来访问这些API。

我在网上找到的一些代码做了如下工作：

extension SingleViewController: UIContextMenuInteractionDelegate {
    func contextMenuInteraction(_ interaction: UIContextMenuInteraction, configurationForMenuAtLocation location: CGPoint) -> UIContextMenuConfiguration? {
        let configuration = UIContextMenuConfiguration(identifier: nil, previewProvider: nil) { actions -> UIMenu<UIAction>? in
            // Creating Save button
            let save = UIAction(__title: "Save", image: UIImage(systemName: "tray.and.arrow.down.fill"), options: []) { action in
                // Just showing some alert
                self.showAlert(title: action.title)
            }

            // Creating Rotate button
            let rotate = UIAction(__title: "Rotate", image: UIImage(systemName: "arrow.counterclockwise"), options: []) { action in
                self.showAlert(title: action.title)
            }
            // Creating Delete button
            let delete = UIAction(__title: "Delete", image: UIImage(systemName: "trash.fill"), options: .destructive) { action in
                self.showAlert(title: action.title)
            }
            // Creating Edit, which will open Submenu
            let edit = UIMenu<UIAction>.create(title: "Edit...", children: [rotate, delete])

            // Creating main context menu
            return UIMenu<UIAction>.create(title: "Menu", children: [save, edit])
        }
        return configuration
    }
}

这似乎很好，但在我的Xcode中甚至没有编译。我所犯的错误是：

Cannot specialize non-generic type 'UIMenu' Replace '<UIAction>' with ''

关于创建配置常量。

Type of expression is ambiguous without more context

关于创建保存操作。

还有其他几个类似的错误。

我还应该指出，我甚至没有这种格式的构造函数：

UIAction(__title: "String", image: UIImage, options: Array)
UIMenu.create(...)

为什么在Xcode-11 beta 3.0中缺少这些？

Answer 1

嗯，它变了。这是个测试版！我希望它会再次改变，但是现在，在beta 3中，UIAction的初始化程序是

init(__title title: String, image: UIImage?, identifier: UIAction.Identifier?, 
    handler: @escaping UIActionHandler)

UIMenu不是泛型的，它的初始化程序是

init(__title title: String, image: UIImage?, identifier: UIMenu.Identifier?, 
    options: UIMenu.Options = [], children: [UIMenuElement])

下面是对在beta 3下编译的代码的重写：

func contextMenuInteraction(_ interaction: UIContextMenuInteraction, configurationForMenuAtLocation location: CGPoint) -> UIContextMenuConfiguration? {
    let configuration = UIContextMenuConfiguration(identifier: nil, previewProvider: nil) { actions -> UIMenu? in
        let save = UIAction(__title: "Save", image: UIImage(systemName: "tray.and.arrow.down.fill"), identifier: nil) { action in
            // whatever
        }
        let rotate = UIAction(__title: "Rotate", image: UIImage(systemName: "arrow.counterclockwise"), identifier: nil) { action in
            // whatever
        }
        let delete = UIAction(__title: "Delete", image: UIImage(systemName: "trash.fill"), identifier: nil) { action in
            // whatever
        }
        let edit = UIMenu(__title: "Edit", image: nil, identifier: nil, children:[rotate,delete])
        return UIMenu(__title: "Menu", image: nil, identifier: nil, children:[save, edit])
    }
    return configuration
}

Answer 2

在Xcode 11.0Beta 5中，您现在可以编写：

extension SingleViewController: UIContextMenuInteractionDelegate {
    func contextMenuInteraction(_ interaction: UIContextMenuInteraction, configurationForMenuAtLocation location: CGPoint) -> UIContextMenuConfiguration? {
        let configuration = UIContextMenuConfiguration(identifier: nil, previewProvider: nil) { actions -> UIMenu? in
            // Creating Save button
            let save = UIAction(title: "Save", image: UIImage(systemName: "tray.and.arrow.down.fill")) { action in
                // Just showing some alert
                self.showAlert(title: action.title)
            }

            // Creating Rotate button
            let rotate = UIAction(title: "Rotate", image: UIImage(systemName: "arrow.counterclockwise")) { action in
                self.showAlert(title: action.title)
            }
            // Creating Delete button
            let delete = UIAction(title: "Delete", image: UIImage(systemName: "trash.fill"), attributes: .destructive) { action in
                self.showAlert(title: action.title)
            }
            // Creating Edit, which will open Submenu
            let edit = UIMenu(title: "Edit...", children: [rotate, delete])

            // Creating main context menu
            return UIMenu(title: "Menu", children: [save, edit])
        }
        return configuration
    }
}

• 这些类不再是泛型的，例如UIMenu而不是UIMenu<UIAction>。
• 综合Swift初始化器允许您删除可选的参数，这些参数具有合理的默认值，例如image、attributes和identifier。
• 不再是UIMenu<UIAction>.create(...)或UIAction(__title:...)。他们现在都是真正的初始化者了，耶！

Answer 3

在斯威夫特5号，这一工作：

extension ViewController: UIContextMenuInteractionDelegate {
func contextMenuInteraction(_ interaction: UIContextMenuInteraction, configurationForMenuAtLocation location: CGPoint) -> UIContextMenuConfiguration? {
    let configuration = UIContextMenuConfiguration(identifier: nil, previewProvider: nil) { actions -> UIMenu? in
        // Creating Save button
        let save = UIAction(title: "Save", image: UIImage(systemName: "tray.and.arrow.down.fill")) { action in
            // Just showing some alert
            self.showAlert(title: action.title)
        }

        // Creating Rotate button
        let rotate = UIAction(title: "Rotate", image: UIImage(systemName: "arrow.counterclockwise")) { action in
            self.showAlert(title: action.title)
        }
        // Creating Delete button
        let delete = UIAction(title: "Delete", image: UIImage(systemName: "trash.fill")) { action in
            self.showAlert(title: action.title)
        }
        // Creating Edit, which will open Submenu
        let edit = UIMenu(title: "Edit...", children: [rotate, delete])

        // Creating main context menu
        return UIMenu(title: "Menu", children: [save, edit])
    }
    return configuration
  }
}