UIViewAnimationOptions.TransitionFlipFromLeft not show UIView second time - ios

Question

I am trying to Flip two UIViews. I've try to flip UIView using programmatically and it works perfect. But when i've try to flip UIView that i created in storyboard it not works, First time it flip UIView but second time it flip blank UiViews? Any one have any idea is there any mistake in my code?
In this picture Top left Debug view Hierarchy picture is before animating button and bottom left Debug view Hierarchy picture is after animating picture.
When second time i animate the UIView it Flip like this below picture.
class ViewController: UIViewController {
#IBOutlet var container: UIView!
#IBOutlet var blueSquare : UIView!
#IBOutlet var redSquare : UIView!
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func animateButtonTapped(sender: AnyObject) {
// create a 'tuple' (a pair or more of objects assigned to a single variable)
var views : (frontView: UIView, backView: UIView)
if ((self.redSquare.superview) != nil) {
views = (frontView: self.redSquare, backView: self.blueSquare)
}
else {
views = (frontView: self.blueSquare, backView: self.redSquare)
}
// set a transition style
let transitionOptions = UIViewAnimationOptions.TransitionFlipFromLeft
// with no animation block, and a completion block set to 'nil' this makes a single line of code
UIView.transitionFromView(views.frontView, toView: views.backView, duration: 1.0, options: transitionOptions, completion: nil)
}
}
Programmatically
That code is perfectly works.
let container = UIView()
let redSquare = UIView()
let blueSquare = UIView()
override func viewDidLoad() {
super.viewDidLoad()
// set container frame and add to the screen
self.container.frame = CGRect(x: 60, y: 60, width: 200, height: 200)
self.view.addSubview(container)
// set red square frame up
// we want the blue square to have the same position as redSquare
// so lets just reuse blueSquare.frame
self.redSquare.frame = CGRect(x: 0, y: 0, width: 200, height: 200)
self.blueSquare.frame = redSquare.frame
// set background colors
self.redSquare.backgroundColor = UIColor.redColor()
self.blueSquare.backgroundColor = UIColor.blueColor()
// for now just add the redSquare
// we'll add blueSquare as part of the transition animation
self.container.addSubview(self.redSquare)
}
#IBAction func animateButtonTapped(sender: AnyObject) {
// create a 'tuple' (a pair or more of objects assigned to a single variable)
var views : (frontView: UIView, backView: UIView)
if((self.redSquare.superview) != nil){
views = (frontView: self.redSquare, backView: self.blueSquare)
}
else {
views = (frontView: self.blueSquare, backView: self.redSquare)
}
// set a transition style
let transitionOptions = UIViewAnimationOptions.TransitionFlipFromLeft
// with no animation block, and a completion block set to 'nil' this makes a single line of code
UIView.transitionFromView(views.frontView, toView: views.backView, duration: 1.0, options: transitionOptions, completion: nil)
}
UPDATE
var check = true
#IBAction func animateButtonTapped(sender: AnyObject) {
// create a 'tuple' (a pair or more of objects assigned to a single variable)
var views : (frontView: UIView, backView: UIView)
if (check == true) {
views = (frontView: self.redSquare, backView: self.blueSquare)
check = false
}
else {
views = (frontView: self.blueSquare, backView: self.redSquare)
check = true
}
// set a transition style
let transitionOptions : UIViewAnimationOptions = [UIViewAnimationOptions.TransitionFlipFromLeft, UIViewAnimationOptions.ShowHideTransitionViews]
// with no animation block, and a completion block set to 'nil' this makes a single line of code
UIView.transitionFromView(views.frontView, toView: views.backView, duration: 1.0, options: transitionOptions, completion: nil)
}

Answer 1

The default behaviour for transitionFromView removes the view after animation.
let transitionOptions: UIViewAnimationOptions = [.TransitionFlipFromLeft, .ShowHideTransitionViews]
From the documentation: https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIView_Class/#//apple_ref/swift/struct/c:#E#UIViewAnimationOptions
ShowHideTransitionViews
When present, this key causes views to be hidden or shown (instead of removed or added) when performing a view transition. Both views must already be present in the parent view’s hierarchy when using this key. If this key is not present, the to-view in a transition is added to, and the from-view is removed from, the parent view’s list of subviews.

Answer 2

Ah in storyboard I see that you add both views to the container but in code you only add the redsquare. Perhaps remove the bluesquare from being within the container in storyboard?