ios - Presenting a UIAlertController properly on an iPad using iOS 8

Question

With iOS 8.0, Apple introduced UIAlertController to replace UIActionSheet. Unfortunately, Apple didn't add any information on how to present it. I found an entry about it on hayaGeek's blog, however, it doesn't seem to work on iPad. The view is totally misplaced:

Misplaced: Misplaced image

Correct: enter image description here

I use the following code to show it on the interface:

    let alert = UIAlertController()
    // setting buttons
    self.presentModalViewController(alert, animated: true)

Is there another way to add it for iPad? Or did Apple just forget the iPad, or not implemented, yet?

score 301 · Accepted Answer

您可以UIAlertController使用UIPopoverPresentationController.

在 Obj-C 中：

UIViewController *self; // code assumes you're in a view controller
UIButton *button; // the button you want to show the popup sheet from

UIAlertController *alertController;
UIAlertAction *destroyAction;
UIAlertAction *otherAction;

alertController = [UIAlertController alertControllerWithTitle:nil
                                                      message:nil
                           preferredStyle:UIAlertControllerStyleActionSheet];
destroyAction = [UIAlertAction actionWithTitle:@"Remove All Data"
                                         style:UIAlertActionStyleDestructive
                                       handler:^(UIAlertAction *action) {
                                           // do destructive stuff here
                                       }];
otherAction = [UIAlertAction actionWithTitle:@"Blah"
                                       style:UIAlertActionStyleDefault
                                     handler:^(UIAlertAction *action) {
                                         // do something here
                                     }];
// note: you can control the order buttons are shown, unlike UIActionSheet
[alertController addAction:destroyAction];
[alertController addAction:otherAction];
[alertController setModalPresentationStyle:UIModalPresentationPopover];

UIPopoverPresentationController *popPresenter = [alertController 
                                              popoverPresentationController];
popPresenter.sourceView = button;
popPresenter.sourceRect = button.bounds;
[self presentViewController:alertController animated:YES completion:nil];

为 Swift 4.2 进行编辑，虽然有很多博客可用于相同的内容，但它可以节省您搜索它们的时间。

if let popoverController = yourAlert.popoverPresentationController {
    popoverController.sourceView = self.view //to set the source of your alert
    popoverController.sourceRect = CGRect(x: self.view.bounds.midX, y: self.view.bounds.midY, width: 0, height: 0) // you can set this as per your requirement.
    popoverController.permittedArrowDirections = [] //to hide the arrow of any particular direction
}

score 116 · Accepted Answer

在 iPad 上，警报将使用新的UIPopoverPresentationController显示为弹出框，它要求您使用 sourceView 和 sourceRect 或 barButtonItem 为弹出框的呈现指定一个锚点

barButtonItem
源视图
源矩形

为了指定锚点，您需要获取对 UIAlertController 的 UIPopoverPresentationController 的引用并设置以下属性之一：

alertController.popoverPresentationController.barButtonItem = button;

示例代码：

UIAlertAction *actionDelete = nil;
UIAlertAction *actionCancel = nil;

// create action sheet
UIAlertController *alertController = [UIAlertController
                                      alertControllerWithTitle:actionTitle message:nil
                                      preferredStyle:UIAlertControllerStyleActionSheet];

// Delete Button
actionDelete = [UIAlertAction
                actionWithTitle:NSLocalizedString(@"IDS_LABEL_DELETE", nil)
                style:UIAlertActionStyleDestructive handler:^(UIAlertAction *action) {

                    // Delete
                    // [self deleteFileAtCurrentIndexPath];
                }];

// Cancel Button
actionCancel = [UIAlertAction
                actionWithTitle:NSLocalizedString(@"IDS_LABEL_CANCEL", nil)
                style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) {
                    // cancel
                    // Cancel code
                }];

// Add Cancel action
[alertController addAction:actionCancel];
[alertController addAction:actionDelete];

// show action sheet
alertController.popoverPresentationController.barButtonItem = button;
alertController.popoverPresentationController.sourceView = self.view;

[self presentViewController:alertController animated:YES
                 completion:nil];

score 88 · Accepted Answer

在 Swift 2 中，您想要执行以下操作以在 iPhone 和 iPad 上正确显示它：

func confirmAndDelete(sender: AnyObject) {
    guard let button = sender as? UIView else {
        return
    }

    let alert = UIAlertController(title: NSLocalizedString("Delete Contact?", comment: ""), message: NSLocalizedString("This action will delete all downloaded audio files.", comment: ""), preferredStyle: .ActionSheet)
    alert.modalPresentationStyle = .Popover

    let action = UIAlertAction(title: NSLocalizedString("Delete", comment: ""), style: .Destructive) { action in
        EarPlaySDK.deleteAllResources()
    }
    let cancel = UIAlertAction(title: NSLocalizedString("Cancel", comment: ""), style: .Cancel) { action in

    }
    alert.addAction(cancel)
    alert.addAction(action)

    if let presenter = alert.popoverPresentationController {
        presenter.sourceView = button
        presenter.sourceRect = button.bounds
    }
    presentViewController(alert, animated: true, completion: nil)
}

如果您不设置演示者，您将在 iPad 上出现异常，-[UIPopoverPresentationController presentationTransitionWillBegin]并显示以下消息：

致命异常：NSGenericException 您的应用程序出现了 UIAlertController (<UIAlertController: 0x17858a00>) 样式 UIAlertControllerStyleActionSheet。具有此样式的 UIAlertController 的 modalPresentationStyle 是 UIModalPresentationPopover。您必须通过警报控制器的 popoverPresentationController 提供此弹出窗口的位置信息。您必须提供 sourceView 和 sourceRect 或 barButtonItem。如果在您呈现警报控制器时不知道此信息，您可以在 UIPopoverPresentationControllerDelegate 方法 -prepareForPopoverPresentation 中提供它。

score 31 · Accepted Answer

斯威夫特 5

我对 iPhone 使用“actionsheet”样式，对 iPad 使用“alert”样式。iPad 显示在屏幕中央。无需在任何地方指定 sourceView 或锚定视图。

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.pad”检查

score 31 · Accepted Answer

Swift 3.0 及更高版本的更新

    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")
    }

score 19 · Accepted Answer

斯威夫特 4 及以上

我创建了一个扩展

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 = []
    }
  }
}

如何使用：

let actionSheetVC = UIAlertController(title: "Title", message: nil, preferredStyle: .actionSheet)
addActionSheetForiPad(actionSheet: actionSheetVC)
present(actionSheetVC, animated: true, completion: nil)

score 16 · Accepted Answer

2018 更新

由于这个原因，我刚刚拒绝了一个应用程序，一个非常快速的解决方案就是从使用操作表更改为警报。

发挥了魅力并顺利通过了 App Store 测试人员。

可能不是适合每个人的答案，但我希望这可以帮助你们中的一些人快速摆脱困境。

score 9 · Accepted Answer

Swift 4.2 你可以使用这样的条件：

let alert = UIAlertController(title: nil, message: nil, preferredStyle: UIDevice.current.userInterfaceIdiom == .pad ? .alert : .actionSheet)

score 8 · Accepted Answer

这是一个快速的解决方案：

NSString *text = self.contentTextView.text;
NSArray *items = @[text];

UIActivityViewController *activity = [[UIActivityViewController alloc]
                                      initWithActivityItems:items
                                      applicationActivities:nil];

activity.excludedActivityTypes = @[UIActivityTypePostToWeibo];

if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad) {
    //activity.popoverPresentationController.sourceView = shareButtonBarItem;

    activity.popoverPresentationController.barButtonItem = shareButtonBarItem;

    [self presentViewController:activity animated:YES completion:nil];

}
[self presentViewController:activity animated:YES completion:nil];

score 5 · Accepted Answer

对我来说，我只需要添加以下内容：

if let popoverController = alertController.popoverPresentationController {
    popoverController.barButtonItem = navigationItem.rightBarButtonItem
}

score 2 · Accepted Answer

只需在展示您的操作表之前添加以下代码：

if let popoverController = optionMenu.popoverPresentationController {
    popoverController.sourceView = self.view
    popoverController.sourceRect = CGRect(x: self.view.bounds.midX, y: self.view.bounds.midY, width: 0, height: 0)
    popoverController.permittedArrowDirections = []
}

score 1 · Accepted Answer

它适用于 iphone 和 ipad

func showImagePicker() {
    var alertStyle = UIAlertController.Style.actionSheet
    if (UIDevice.current.userInterfaceIdiom == .pad) {
      alertStyle = UIAlertController.Style.alert
    }
    let alert = UIAlertController(title: "", message: "Upload Attachment", preferredStyle: alertStyle)
    alert.addAction(UIAlertAction(title: "Choose from gallery", style: .default , handler:{ (UIAlertAction) in
        self.pickPhoto(sourceType: .photoLibrary)
    }))
    alert.addAction(UIAlertAction(title: "Take Photo", style: .default, handler:{ (UIAlertAction) in
        self.pickPhoto(sourceType: .camera)
    }))
    alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler:{ (UIAlertAction) in
    }))
    present(alert, animated: true, completion: nil)
}

score 0 · Accepted Answer

如果您的代码库同时支持 iPhone 和 iPad 设备，请考虑以下

present(_ viewControllerToPresent:animated:completion:)在以下情况下定期使用：

呈现一个UIAlertControllerwith preferredStyleof.alert
提出UIViewController一个.modalPresentationStyle：
- .overFullScreen
- .formSheet
- .automatic 如果modalPresentationStyle未指定默认值
- .currentContext
- .fullScreen
- .custom
- .overCurrentContext

在以下情况下配置popoverPresentationController'ssourceRect和sourceView呈现之前：

呈现一个UIAlertControllerwith preferredStyleof.actionSheet
提出UIViewController一个.modalPresentationStyle：
- .popover
- .none 这将在 iPhone 和 iPad 上崩溃，并显示错误“指定的模式演示样式没有相应的演示控制器”。
呈现一个UIActivityViewController（基于https://developer.apple.com/documentation/uikit/uiactivityviewcontroller；“在 iPad 上，您必须在弹出窗口中呈现视图控制器。在 iPhone 和 iPod touch 上，您必须以模态方式呈现它。”）

下面是一个配置示例popoverPresentationController

if let popoverController = popoverPresentationController {
  popoverController.sourceView = view
  popoverController.sourceRect = CGRect(x: view.bounds.maxX, y: 40, width: 0, height: 0)
}

如果您发现此处未列出的任何其他案例，请告诉我！

ios - Presenting a UIAlertController properly on an iPad using iOS 8

13 回答 13

在 Obj-C 中：

Related

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