Custom animation when hiding UINavigationBar - objective-c

Question

I'm making an application which shows/hides (in custom animation) the UINavigationBar on single tap.
I have created two functions (one for showing and the other for hiding). The function for showing the UINavigationBar works perfectly:
- (void) showNavigationBar {
[UINavigationBar beginAnimations:#"NavBarFadeIn" context:nil];
self.navigationController.navigationBar.alpha = 0;
[UINavigationBar setAnimationCurve:UIViewAnimationCurveEaseIn];
[UINavigationBar setAnimationDuration:0.5];
[UINavigationBar setAnimationTransition:UIViewAnimationOptionTransitionFlipFromTop
forView:self.navigationController.navigationBar
cache:YES];
self.navigationController.navigationBar.alpha = 1;
[UINavigationBar commitAnimations];
}
But the function for hiding it, even if it's the same, doesn't work. The UINavigationBar disappears suddenly with no animation.
- (void) hideNavigationBar {
[UINavigationBar beginAnimations:#"NavBarFadeOut" context:nil];
self.navigationController.navigationBar.alpha = 1;
[UINavigationBar setAnimationCurve:UIViewAnimationCurveEaseIn];
[UINavigationBar setAnimationDuration:0.5];
[UINavigationBar setAnimationTransition:UIViewAnimationOptionTransitionCurlUp
forView:self.navigationController.navigationBar
cache:YES];
self.navigationController.navigationBar.alpha = 0;
[self.navigationController setNavigationBarHidden:YES animated:NO];
[UINavigationBar commitAnimations];
}
The calling:
- (void)contentView:(ReaderContentView *)contentView touchesBegan:(NSSet *)touches
{
if( [[self navigationController] isNavigationBarHidden] == NO)
{
if (touches.count == 1) // Single touches only
{
UITouch *touch = [touches anyObject]; // Touch info
CGPoint point = [touch locationInView:self.view]; // Touch location
CGRect areaRect = CGRectInset(self.view.bounds, TAP_AREA_SIZE, TAP_AREA_SIZE);
if (CGRectContainsPoint(areaRect, point) == false) return;
}
[mainToolbar hideToolbar];
[mainPagebar hidePagebar]; // Hide
[self hideNavigationBar];
lastHideTime = [NSDate new];
}
}
Anybody has a clue about why this is happening?

Answer 1

It is happening, because you are calling [self.navigationController setNavigationBarHidden:YES animated:NO]; in the animation code but boolian values are not animatable. There is no "in between values" for bool values.
You should call [self.navigationController setNavigationBarHidden:YES animated:NO]; in a method which you schedule after the animation with
[UINavigationBar setAnimationDidStopSelector: #selector(myCoolMethod:)];