Core Animation Strange Display after addSubview then removeFromSuperview - ios

Question

I have a view controller with a central container that gets flipped to show different views on each side. One of the views is a table view and the other is a custom view of mine. It is working perfectly as per screenshot 1.
My problem is that after I have added a subview over this viewcontroller (its a transparent UIView for showing help screen) and then remove this subview from the viewcontroller
, when I try re-flip the central view strange results occur. There still seems to be a flipping animation between the two views, but as you can see from the last 2 screenshot an extra central table view just sits there. I can't quite explain this exactly so I'm hoping a combination of the pictures, and some code will help:
MainPageVC.h
#interface MainPageVC : UIViewController <UITableViewDataSource, UITableViewDelegate>
#end
MainPageVC.m
#interface MainPageVC ()
#property (nonatomic, strong) NSArray *dataArr;
#property (nonatomic, weak) IBOutlet UIView *flipContainerView;
#property (nonatomic, strong) UIView *detailFlipView;
#property (nonatomic, strong) UITableView *listFlipView;
#property (nonatomic) BOOL isTransitioning;
#property (nonatomic) BOOL isFlipped;
#end
#implementation MainPageVC
#synthesize dataArr = _dataArr;
#synthesize flipContainerView = _flipContainerView;
#synthesize detailFlipView = _detailFlipView;
#synthesize listFlipView = _listFlipView;
#synthesize isTransitioning = _isTransitioning;
#synthesize isFlipped = _isFlipped;
- (void)viewDidLoad {
[super viewDidLoad];
self.dataArr = [NSArray arrayWithObjects:#"row 1", #"row 2", #"row 3", nil];;
}
- (void)viewDidLayoutSubviews {
[self setUpCustomViews];
}
- (void)setUpCustomViews {
self.isFlipped = NO;
self.isTransitioning = NO;
CGRect frame = CGRectMake(0, 0, self.flipContainerView.frame.size.width, self.flipContainerView.frame.size.height);
self.detailFlipView = [[UIView alloc] initWithFrame:frame];
UIView *customView = [[UIView alloc] initWithFrame:CGRectMake(0,0,50,50)];
[self.detailFlipView addSubview:customView];
self.listFlipView = [[UITableView alloc] initWithFrame:frame];
self.listFlipView.delegate = self;
self.listFlipView.dataSource = self;
UIColor *backgroundColour = [UIColor whiteColor];
CGFloat cornerRadius = 15.0f;
CGFloat borderWidth = 1.5f;
UIColor *borderColour = [UIColor colorWithRed:49.0/255.0f green:49.0/255.0f blue:49.0/255.0f alpha:1.0f];
self.detailFlipView.backgroundColor = backgroundColour;
self.listFlipView.backgroundColor = backgroundColour;
self.detailFlipView.layer.cornerRadius = cornerRadius;
self.listFlipView.layer.cornerRadius = cornerRadius;
self.detailFlipView.layer.borderWidth = borderWidth;
self.listFlipView.layer.borderWidth = borderWidth;
self.detailFlipView.layer.borderColor = [borderColour CGColor];
self.listFlipView.layer.borderColor = [borderColour CGColor];
self.detailFlipView.layer.doubleSided = NO;
self.listFlipView.layer.doubleSided = NO;
self.listFlipView.layer.masksToBounds = YES;
self.detailFlipView.layer.masksToBounds = YES;
[self.flipContainerView addSubview:self.detailFlipView];
[self.flipContainerView addSubview:self.listFlipView];
}
- (IBAction)changeViewTapped:(UIControl *)sender {
if (self.isTransitioning) return;
CALayer *top = self.listFlipView.layer;
CALayer *bottom = self.detailFlipView.layer;
if (self.isFlipped) {
top = self.detailFlipView.layer;
bottom = self.listFlipView.layer;
}
CAAnimation *topAnimation = [self flipAnimationWithDuration:0.6f forLayerBeginningOnTop:YES scaleFactor:1.2f];
CAAnimation *bottomAnimation = [self flipAnimationWithDuration:0.6f forLayerBeginningOnTop:NO scaleFactor:1.2f];
CGFloat zDistance = 1000.0f;
CATransform3D perspective = CATransform3DIdentity;
perspective.m34 = -1. / zDistance;
top.transform = perspective;
bottom.transform = perspective;
topAnimation.delegate = self;
[CATransaction begin];
[top addAnimation:topAnimation forKey:#"flip"];
[bottom addAnimation:bottomAnimation forKey:#"flip"];
CABasicAnimation *colorAnimation = [CABasicAnimation animationWithKeyPath:#"backgroundColor"];
colorAnimation.toValue = (id)[UIColor colorWithRed:27.0/255.0f green:47.0/255.0f blue:87.0/255.0f alpha:1.0f].CGColor;
[self.bannerButtonImageView.layer addAnimation:colorAnimation forKey:#"colorAnimation"];
[CATransaction commit];
}
-(CAAnimation *)flipAnimationWithDuration:(NSTimeInterval)aDuration forLayerBeginningOnTop:(BOOL)beginsOnTop scaleFactor:(CGFloat)scaleFactor {
self.isTransitioning = YES;
CABasicAnimation *flipAnimation = [CABasicAnimation animationWithKeyPath:#"transform.rotation.y"];
CGFloat startValue = beginsOnTop ? 0.0f : M_PI;
CGFloat endValue = beginsOnTop ? -M_PI : 0.0f;
flipAnimation.fromValue = [NSNumber numberWithDouble:startValue];
flipAnimation.toValue = [NSNumber numberWithDouble:endValue];
CABasicAnimation *shrinkAnimation = nil;
if (scaleFactor != 1.0f ) {
shrinkAnimation = [CABasicAnimation animationWithKeyPath:#"transform.scale"];
shrinkAnimation.toValue = [NSNumber numberWithFloat:scaleFactor];
shrinkAnimation.duration = aDuration * 0.5;
shrinkAnimation.autoreverses = YES;
}
CAAnimationGroup *animationGroup = [CAAnimationGroup animation];
animationGroup.animations = [NSArray arrayWithObjects:flipAnimation, shrinkAnimation, nil];
animationGroup.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
animationGroup.duration = aDuration;
animationGroup.fillMode = kCAFillModeForwards;
animationGroup.removedOnCompletion = NO;
return animationGroup;
}
-(void)animationDidStop:(CAAnimation *)animation finished:(BOOL)flag {
self.isFlipped = !self.isFlipped;
self.isTransitioning = NO;
}
...USUAL UITABLEVIEW METHODS
- (void)showHelpScreen {
CustomHelp *helpView = [[CustomHelp alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
[self.view addSubview:helpView];
}
#end
CustomHelp.h
#interface CustomHelp : UIView
#end
CustomHelp.m
#implementation CustomHelp
- (id)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
UIView *test = [[UIView alloc] initWithFrame:CGRectMake(20, 20, 50, 100)];
test.backgroundColor = [UIColor redColor];
[self addSubview:test];
UITapGestureRecognizer* singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(handleSingleTap)];
singleTap.numberOfTapsRequired = 1;
singleTap.numberOfTouchesRequired = 1;
[self addGestureRecognizer: singleTap];
}
return self;
}
- (void)handleSingleTap {
[UIView animateWithDuration:0.5
animations:^{ self.alpha = 0.0;}
completion:^(BOOL finished){
[self removeFromSuperview];
}];
}
#end

Answer 1

Adding comment as answer.
My only suggestion would be in the setUpCustomViews function to add in an if(!self.listFlipView) and if(!self.detailFlipView) to the view creation. That function may be being called multiple times and thereby adding multiple views to your window without removing the previous one.