我正在尝试使用iOS 13.0 Beta中引入的新API。我已经下载了Xcode 11.0 Beta 3,以便能够访问这些API。
我在网上找到的一些代码是这样的:
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
}
}
这看起来不错,但甚至无法在我的 Xcode 中编译。我得到的错误是:
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
创建保存操作时。
并有几个其他类似的错误。
我还应该提到,我什至没有这种格式的构造函数:
UIAction(__title: "String", image: UIImage, options: Array)
UIMenu.create(...)
为什么这些在 Xcode-11 beta 3.0 中缺失?
嗯,它变了。这是一个测试版!我希望它会再次更改,但目前,在 beta 3 中,UIAction 的初始值设定项是
init(__title title: String, image: UIImage?, identifier: UIAction.Identifier?,
handler: @escaping UIActionHandler)
UIMenu 不是泛型的,其初始值设定项是
init(__title title: String, image: UIImage?, identifier: UIMenu.Identifier?,
options: UIMenu.Options = [], children: [UIMenuElement])
因此,这是在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
}
在 Xcode 11.0 Beta 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
}
}
- 这些类不再是通用的,例如
UIMenu
而不是UIMenu<UIAction>
. - 全面的 Swift 初始值设定项允许您删除具有合理默认值的可选参数,例如
image
,attributes
和identifier
。 - 不再
UIMenu<UIAction>.create(...)
或UIAction(__title:...)
.它们现在都是真正的初始值设定项,耶!
在 swift 5 上,这有效:
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
}
}