在iOS 8.0中，苹果引入了UIAlertController来取代UIActionSheet。不幸的是，苹果没有提供任何关于如何展示的信息。我在hayaGeek的博客上找到了一个关于它的条目，然而，它似乎不能在iPad上运行。这种观点是完全错误的:
错误的:
正确的:
我使用以下代码在界面上显示它:
let alert = UIAlertController()
// setting buttons
self.presentModalViewController(alert, animated: true)
是否有其他方法添加到iPad上?或者苹果只是忘记了iPad，或者还没有推出iPad ?
当前回答
如果您的代码库同时支持iPhone和iPad设备，请考虑以下内容
在以下情况下定期使用present(_ viewcontrollertoppresent:animated:completion:)
呈现一个preferredStyle为.alert的UIAlertController 用.modalPresentationStyle表示一个UIViewController: .overFullScreen .formSheet .automatic未指定modalPresentationStyle时的默认值 .currentContext .fullScreen .custom .overCurrentContext
在呈现前配置popoverPresentationController的sourceRect和sourceView:
Presenting a UIAlertController with preferredStyle of .actionSheet Presenting a UIViewController with .modalPresentationStyle of: .popover .none This will crash on both iPhone and iPads with the error "The specified modal presentation style doesn't have a corresponding presentation controller." Presenting a UIActivityViewController (Based on https://developer.apple.com/documentation/uikit/uiactivityviewcontroller ; "On iPad, you must present the view controller in a popover. On iPhone and iPod touch, you must present it modally.")
下面是一个配置popoverPresentationController的例子
if let popoverController = popoverPresentationController {
popoverController.sourceView = view
popoverController.sourceRect = CGRect(x: view.bounds.maxX, y: 40, width: 0, height: 0)
}
如果你发现这里没有列出的其他案例，请告诉我!
其他回答
斯威夫特5
我在iPhone上使用“actionsheet”样式，在iPad上使用“alert”样式。iPad显示在屏幕中央。不需要指定sourceView或将视图锚定在任何位置。
var alertStyle = UIAlertController.Style.actionSheet
if (UIDevice.current.userInterfaceIdiom == .pad) {
alertStyle = UIAlertController.Style.alert
}
let alertController = UIAlertController(title: "Your title", message: nil, preferredStyle: alertStyle)
编辑:根据ShareToD的建议，更新了已弃用的“UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiom.”垫“检查
Swift 4及以上
我已经创建了一个扩展
extension UIViewController {
public func addActionSheetForiPad(actionSheet: UIAlertController) {
if let popoverPresentationController = actionSheet.popoverPresentationController {
popoverPresentationController.sourceView = self.view
popoverPresentationController.sourceRect = CGRect(x: self.view.bounds.midX, y: self.view.bounds.midY, width: 0, height: 0)
popoverPresentationController.permittedArrowDirections = []
}
}
}
使用方法:
let actionSheetVC = UIAlertController(title: "Title", message: nil, preferredStyle: .actionSheet)
addActionSheetForiPad(actionSheet: actionSheetVC)
present(actionSheetVC, animated: true, completion: nil)
如果您的代码库同时支持iPhone和iPad设备，请考虑以下内容
在以下情况下定期使用present(_ viewcontrollertoppresent:animated:completion:)
呈现一个preferredStyle为.alert的UIAlertController 用.modalPresentationStyle表示一个UIViewController: .overFullScreen .formSheet .automatic未指定modalPresentationStyle时的默认值 .currentContext .fullScreen .custom .overCurrentContext
在呈现前配置popoverPresentationController的sourceRect和sourceView:
Presenting a UIAlertController with preferredStyle of .actionSheet Presenting a UIViewController with .modalPresentationStyle of: .popover .none This will crash on both iPhone and iPads with the error "The specified modal presentation style doesn't have a corresponding presentation controller." Presenting a UIActivityViewController (Based on https://developer.apple.com/documentation/uikit/uiactivityviewcontroller ; "On iPad, you must present the view controller in a popover. On iPhone and iPod touch, you must present it modally.")
下面是一个配置popoverPresentationController的例子
if let popoverController = popoverPresentationController {
popoverController.sourceView = view
popoverController.sourceRect = CGRect(x: view.bounds.maxX, y: 40, width: 0, height: 0)
}
如果你发现这里没有列出的其他案例，请告诉我!
斯威夫特5
适用于iPad和iPhone。
动作表下方悬停一个按钮
对于iPhone，动作表将显示正常，iPad将显示在按钮下方。
actionSheet.popoverPresentationController?.sourceView = fooButton
actionSheet.popoverPresentationController?.sourceRect = fooButton.bounds
动作表在屏幕/视图的中间
对于iPhone，动作表将正常显示，iPad将显示在屏幕/视图的中间。
actionSheet.popoverPresentationController?.sourceView = view
actionSheet.popoverPresentationController?.sourceRect = CGRect(x: view.bounds.midX, y: view.bounds.midY, width: 0, height: 0)
actionSheet.popoverPresentationController?.permittedArrowDirections = []
Swift 3.0及更高版本更新
let actionSheetController: UIAlertController = UIAlertController(title: "SomeTitle", message: nil, preferredStyle: .actionSheet)
let editAction: UIAlertAction = UIAlertAction(title: "Edit Details", style: .default) { action -> Void in
print("Edit Details")
}
let deleteAction: UIAlertAction = UIAlertAction(title: "Delete Item", style: .default) { action -> Void in
print("Delete Item")
}
let cancelAction: UIAlertAction = UIAlertAction(title: "Cancel", style: .cancel) { action -> Void in }
actionSheetController.addAction(editAction)
actionSheetController.addAction(deleteAction)
actionSheetController.addAction(cancelAction)
// present(actionSheetController, animated: true, completion: nil) // doesn't work for iPad
actionSheetController.popoverPresentationController?.sourceView = yourSourceViewName // works for both iPhone & iPad
present(actionSheetController, animated: true) {
print("option menu presented")
}
