Swift Unbalanced calls to begin/end appearance transitions for

问题

This has been stumping me for a while now. I have a UISplitViewController inside a UITabBarController. The master view is a TableView. When I click on a cell, I bring up a very basic view controller with just a UIButton centered. Here is the code for the view controller:

class TestViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
    @IBOutlet weak var button: UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    @IBAction func buttonPressed(sender: AnyObject) {
        let pickerC = UIImagePickerController()
        pickerC.delegate = self

        pickerC.modalPresentationStyle = .Popover
        pickerC.popoverPresentationController?.sourceView = button as UIView
        pickerC.popoverPresentationController?.sourceRect = (button as UIView).bounds
        pickerC.popoverPresentationController?.permittedArrowDirections = UIPopoverArrowDirection.Any
        self.presentViewController(pickerC, animated: true, completion: nil)//4
    }

    func imagePickerController(picker: UIImagePickerController, didFinishPickingImage image: UIImage!, editingInfo: [NSObject : AnyObject]!) {
        self.dismissViewControllerAnimated(true, completion: nil)
    }

    func imagePickerControllerDidCancel(picker: UIImagePickerController) {
       self.dismissViewControllerAnimated(true, completion: nil)
    }
}

If I click cancel or select and image, the picker controller dismisses properly. The problem comes when I click on the back button to return to the TableView, I receive:

Unbalanced calls to begin/end appearance transitions for <TestViewController: 0x7fb882a72380>.

The TestViewController is very basic, so why would this be happening?

回答1:

This issue occurs if you trying to push new view controller while previous transaction (animation) in progress. So please check your code flow and make the appropriate changes. Check your dismiss and present view animations. You can use property setAnimation to 'YES/NO'resolve this

Set animated:NO, may be solve your problem

回答2:

To me this weird issue was occurring due to following line after implementation of UISplitViewController

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
.
.
.
    // splitViewController.preferredDisplayMode = .PrimaryOverlay
.
.
.
    }

By commenting this line in didFinishLaunchingWithOptions issue was resolved.

来源：https://stackoverflow.com/questions/30061153/swift-unbalanced-calls-to-begin-end-appearance-transitions-for

标签

ios

swift

uiviewcontroller

uiimagepickercontroller