我想在 UIPopoverPresentationController 中呈现一个 viewController，就像我们选择语言时 iOS Setting App 所做的那样。它在设备屏幕的中心呈现了一个 viewController！
但是，我的结果不是这样的！
这是我的代码：
func rightButtonPressed(rightBarButton: UIBarButtonItem) {
let detailVC = self.storyboard?.instantiateViewControllerWithIdentifier("ExampleViewController") as! ExampleViewController
detailVC.modalPresentationStyle = .Popover
let popOverVC = detailVC.popoverPresentationController
popOverVC?.permittedArrowDirections = .Any
popOverVC?.barButtonItem = rightBarButton
popOverVC?.sourceView = self.view
popOverVC?.delegate = self
self.presentViewController(detailVC, animated: true, completion: nil)
}
和代表：
extension DetailViewController: UIPopoverPresentationControllerDelegate {
func adaptivePresentationStyleForPresentationController(controller: UIPresentationController) -> UIModalPresentationStyle {
debugPrint(controller.description)
return .Popover
}
func presentationController(controller: UIPresentationController, viewControllerForAdaptivePresentationStyle style: UIModalPresentationStyle) -> UIViewController? {
let navController = UINavigationController.init(rootViewController: controller.presentedViewController)
return navController
}
}