导航collectionview时导航栏损坏

Question

I'm building a tab bar application that consists of 4 tabs. Each tab is a collectionviewcontroller embedded in a navigation controller. I am encountering an issue with the first view controller that loads.

The first view controller is a subclass of uicollectionviewcontroller, as stated above. The collection consists of different types of cells. When each cell is selected, I perform a segue to a new view controller containing the details of that cell. When I tap into a cell, and then swipe right to go back, I get the following error:

nested push animation can result in corrupted navigation bar

There are many topics on this site regarding this specific error message. I've read them all and still can't solve this. My error is particularly strange for a few reasons:

• It only happens when I swipe back (rather than pressing the back button in the navigation controller)
• It only happens when I haven't gone to any other tabs in the application. If I open the application, go to another tab, and then go back to the default tab, the navigation works perfectly.

For reference, here is some of my relevant code (sorry it's messy):

override func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
    var segueId: String?
    switch self.cards[indexPath.item].type {
        case "standard", "text":
            segueId = "showCard"
            break
        case "question":
            segueId = "showQuestion"
            break
        default:
            segueId = nil
            break
    }
    if let sequeId = segueId {
        self.performSegueWithIdentifier(segueId!, sender: self)
    }
}


override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

    if segue.identifier == "showCard" {
        let indexPaths = collectionView!.indexPathsForSelectedItems()
        let indexPath = indexPaths![0] as NSIndexPath
        let vc = segue.destinationViewController as! CardDetailViewController
        let selectedCard = self.cards[indexPath.item]
        vc.cardTitle = selectedCard.headline
        vc.cardImage = selectedCard.image
        vc.files = selectedCard.files
        vc.cardBody = selectedCard.text

        // set imageview dimensions
        let screenSize: CGRect = UIScreen.mainScreen().bounds
        let screenWidth = screenSize.width
        let boundingRect = CGRect(x: 0, y: 0, width: screenWidth, height: CGFloat(MAXFLOAT))
        if selectedCard.image != nil {
            let rect = AVMakeRectWithAspectRatioInsideRect(selectedCard.image!.size, boundingRect)
            vc.heightOfImage = rect.height
        } else {
            vc.heightOfImage = 0
        }
    }

    if segue.identifier == "showQuestion" {
        let indexPaths = collectionView!.indexPathsForSelectedItems()
        let indexPath = indexPaths![0] as NSIndexPath
        let vc = segue.destinationViewController as! QuestionAnswerViewController
        let selectedCard = self.cards[indexPath.item]
        vc.questionText = selectedCard.headline
        vc.smartEvent = selectedCard.event
        vc.smartLocation = selectedCard.smartLocation
        vc.cardId = selectedCard.cardID
    }

}

Thanks in advance for any help.

Answer 1

I figured it out. I had overridden viewDidAppear in the tab bar controller, without calling super.viewDidAppear().