Swift-導航控制器無須殺死View控制器實例

Question

我正在使用自定義導航控制器來顯示和隱藏兩個ViewController。 調用ViewController來顯示電影細節​​的代碼是：

func tapGestureRecognizer(gestureRecognizer: UITapGestureRecognizer){
        self.searchBarTop.endEditing(true)
        let p = gestureRecognizer.locationInView(self.collectionViewMovies)
        let tag = gestureRecognizer.view?.tag
        if tag == 1{
            if let indexPath : NSIndexPath = (self.collectionViewMovies?.indexPathForItemAtPoint(p)){
                if let cell = self.collectionViewMovies.cellForItemAtIndexPath(indexPath){
                    cellAnimation.imageBlurCell(cell, style: .Light, alpha: 1.0, completion: { (complete) -> Void in
                        if let record = self.fetchedResultsController.objectAtIndexPath(indexPath) as? Movies{
                            let movieId = record.movieid as! Int
                            NSNotificationCenter.defaultCenter().postNotificationName("moviesShouldGetDetails", object: nil, userInfo: ["movieId":movieId])
                            let destination = self.myStoryboard.instantiateViewControllerWithIdentifier("MovieDetails") as! MovieDetailsViewController
                            destination.movieId = movieId
                            self.navigationController?.pushViewController(destination, animated: true)
                        }
                    })
                }
            }
        }
    }

我每次都創建一個MovieDetailsViewController的新實例。 問題是，我認為在NavigationController彈出ViewController之后，該實例將被殺死，但這並沒有發生變化。 我在MovieDetailsViewController內部有一些觀察者，我可以看到實例仍在運行。 NavigationController委托為：

func navigationController(navigationController: UINavigationController, animationControllerForOperation operation: UINavigationControllerOperation, fromViewController fromVC: UIViewController, toViewController toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        if operation == .Push {
            customInteractionController.attachToViewController(toVC)
        }
        customNavigationAnimationController.reverse = operation == .Pop
        return customNavigationAnimationController
    }

    func navigationController(navigationController: UINavigationController, interactionControllerForAnimationController animationController: UIViewControllerAnimatedTransitioning) -> UIViewControllerInteractiveTransitioning? {
        return customInteractionController.transitionInProgress ? customInteractionController : nil
    }

下面是控制動畫的代碼，當動畫完成時，我試圖再次強制導航彈出窗口，但到目前為止還算運氣。

import UIKit

class CustomNavigationAnimationController: NSObject, UIViewControllerAnimatedTransitioning {

    var reverse = false

    func transitionDuration(transitionContext: UIViewControllerContextTransitioning?) -> NSTimeInterval {
        return 0.5
    }

    func animateTransition(transitionContext: UIViewControllerContextTransitioning) {
        let containerView = transitionContext.containerView()
        let toViewController = transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey)!
        let fromViewController = transitionContext.viewControllerForKey(UITransitionContextFromViewControllerKey)!
        let toView = toViewController.view
        let fromView = fromViewController.view
        let direction: CGFloat = reverse ? -1 : 1
        let const: CGFloat = -0.005

        toView.layer.anchorPoint = CGPointMake(direction == 1 ? 0 : 1, 0.5)
        fromView.layer.anchorPoint = CGPointMake(direction == 1 ? 1 : 0, 0.5)

        var viewFromTransform: CATransform3D = CATransform3DMakeRotation(direction * CGFloat(M_PI_2), 0.0, 1.0, 0.0)
        var viewToTransform: CATransform3D = CATransform3DMakeRotation(-direction * CGFloat(M_PI_2), 0.0, 1.0, 0.0)
        viewFromTransform.m34 = const
        viewToTransform.m34 = const

        containerView!.transform = CGAffineTransformMakeTranslation(direction * containerView!.frame.size.width / 2.0, 0)
        toView.layer.transform = viewToTransform
        containerView!.addSubview(toView)

        UIView.animateWithDuration(transitionDuration(transitionContext), animations: {
            containerView!.transform = CGAffineTransformMakeTranslation(-direction * containerView!.frame.size.width / 2.0, 0)
            fromView.layer.transform = viewFromTransform
            toView.layer.transform = CATransform3DIdentity
            }, completion: {
                finished in
                containerView!.transform = CGAffineTransformIdentity
                fromView.layer.transform = CATransform3DIdentity
                toView.layer.transform = CATransform3DIdentity
                fromView.layer.anchorPoint = CGPointMake(0.5, 0.5)
                toView.layer.anchorPoint = CGPointMake(0.5, 0.5)

                if (transitionContext.transitionWasCancelled()) {
                    toView.removeFromSuperview()
                } else {
                    fromView.removeFromSuperview()
                    if self.reverse{
                        print("removing from superview")
                        fromViewController.navigationController?.popViewControllerAnimated(false)
                    }
                }
                transitionContext.completeTransition(!transitionContext.transitionWasCancelled())
        })
    }
}

我在這里想念什么？ 如何殺死我的MovieDetailsViewController實例？ NavigationController .Pop應該不會殺死我的實例？ 提前致謝。

Answer 1

你說

我在MovieDetailsViewController內部有一些觀察者，我可以看到實例仍在運行。

這是否可能意味着您在彈出后仍保留對MovieDetailsViewController的引用？ Swift的垃圾收集器將不再釋放視圖控制器，直到它不再具有任何引用為止。 如果您維護對視圖控制器的引用，即使不在屏幕上，它也將保持活動狀態。

Answer 2

花了一段時間了解ARC的工作原理后，我得以解決該問題。 我有一些強大的參考周期，因為有些委托沒有被聲明為“弱”。 另一個問題是這條線

customInteractionController.attachToViewController(toVC)

這段代碼將在另一個類中創建帶有NavigationViewController的Strong Reference，我只是將此引用更改為weak。 現在一切正常。