Xcode 8 Swift 3：未调用模态表示转换委托 [英] Xcode 8 Swift 3: Modal presentation transitioning delegate not called

问题描述

问题

DrinkTransitioningDelegate中的委托函数未调用。 'td'实例在演示文稿的生命周期之内和之外都保留在内存中。

The delegate functions within 'DrinkTransitioningDelegate' are not called. The 'td' instance remains in memory during and beyond the lifecycle of the presentation.

class PresentingViewController: UIViewController {

    let td = DrinkTransitioningDelegate()

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        let item = inventory.beverages[indexPath.row]
        item.isSelected = true
        let controller = DrinkViewController(item: item)
        controller.delegate = self
        controller.transitioningDelegate = td
        controller.modalPresentationStyle = .custom
        //let navCon = UINavigationController(rootViewController: controller)
        //navCon.transitioningDelegate = td
        //navCon.modalPresentationStyle = .custom
        present(controller, animated: true)
    }

}

class DrinkTransitioningDelegate: NSObject, UIViewControllerTransitioningDelegate {

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

    let animationController = DrinkAnimatedTransition()

    func animationControllerForPresentedController(presented: UIViewController, presentingController presenting: UIViewController, sourceController source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        animationController.isPresentation = true
        return animationController
    }

    func animationControllerForDismissedController(dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        animationController.isPresentation = false
        return animationController
    }

    deinit {
        print("adf")
    }

}

历史

• 对于iOS 7提出了这个问题此处


• 该问题是针对iOS 9 在这里

• The question was raised for iOS 7 here
• The question was raised for iOS 9 here

推荐答案

可选协议功能现在已经成为现实。

Optional protocol functions are now a thing.

委托完全由可选功能组成，因此没有警告。

The delegate is comprised completely of optional functions, so there were no warnings.

这些函数作为我自己的自定义函数出现在编译器中。

These functions appeared to the compiler as my own custom functions.

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

let animationController = DrinkAnimatedTransition()

func animationControllerForPresentedController(presented: UIViewController, presentingController presenting: UIViewController, sourceController source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
    animationController.isPresentation = true
    return animationController
}

func animationControllerForDismissedController(dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
    animationController.isPresentation = false
    return animationController
}

这些是正确的功能。

func presentationController(forPresented presented: UIViewController, presenting: UIViewController?, source: UIViewController) -> UIPresentationController? {
    return DrinkPresentationViewController(presentedViewController:presented, presenting: presenting)
}

func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
    let animationController = DrinkAnimatedTransition()
    animationController.isPresentation = true
    return animationController
}

func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
    let animationController = DrinkAnimatedTransition()
    animationController.isPresentation = false
    return animationController
}

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