我正在通过src和FBSDKLoginButton在Facebook上实施单点登录。
成功登录后，该按钮将更改为注销 - 点击后，Facebook实施会在操作表样式中显示FBSDKLoginButtonDelegate以确认注销。这会在iPad上崩溃应用程序，但错误：
UIAlertController
有没有办法改变此'NSGenericException', reason: 'Your application has presented a UIAlertController (<UIAlertController: 0x7fce37e4f3d0>) of style UIAlertControllerStyleActionSheet. The modalPresentationStyle of a UIAlertController with this style is UIModalPresentationPopover. You must provide location information for this popover through the alert controller's popoverPresentationController. You must provide either a sourceView and sourceRect or a barButtonItem. If this information is not known when you present the alert controller, you may provide it in the UIPopoverPresentationControllerDelegate method -prepareForPopoverPresentation.'的隐藏实现以指示UIAlertController.popoverPresentationController？