swift - 当分离到从NSObject继承的自定义类时，TransitioningDelegate对UIPresentationController不起作用

我使用自定义的uipresentationcontroller用自己的动画来执行续集。在prepareForSegue:

myDestinationController.transitioningDelegate = DBViewControllerTransitioningDelegate()
myDestinationController.modalPresentationStyle = .Custom

这是我的：

class DBViewControllerTransitioningDelegate: NSObject, UIViewControllerTransitioningDelegate {

    func presentationControllerForPresentedViewController(presented: UIViewController, presentingViewController presenting: UIViewController, sourceViewController source: UIViewController) -> UIPresentationController? {
        return DBOverlayPresentationController(presentedViewController: presented, presentingViewController: presenting)
    }

    func animationControllerForPresentedController(presented: UIViewController, presentingController presenting: UIViewController, sourceController source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        return DBTransitioningAnimator()
    }
}

它不起作用，因为方法没有被调用。但当我设定：

myDestinationController.transitioningDelegate = self

在MyDBViewControllerTransitioningDelegate控制器中添加两个Myself方法，一切都很好。这两种方法被调用。为什么？有什么区别？

最佳答案

transitioningDelegate中UIViewController的声明：
weak var transitioningDelegate: UIViewControllerTransitioningDelegate?
如您所见，持有transitioningDelegate引用。自定义TransitioningDelegate实例在您创建后立即被释放，因为这里没有人拥有所有权。当您在“控制器”中采用委托并将其分配给“某人”时，将为您保留此委托实例。

关于swift - 当分离到从NSObject继承的自定义类时，TransitioningDelegate对UIPresentationController不起作用，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/31109704/