iOS 7 navigationBar repositioning after dismissViewController - ios

Question

I have a controller embedded in navigation controller. Let's say that i have a button that repositions self.navigationController.navigationBar a bit. Then i do presentViewControllerAnimated with any controller (doesn't matter if it's nav or not) and after dismissing it navigation bar returns to it's original position (actually it is at its original position at dismiss animation start). In iOS 6 and earlier the bar would not be repositioned automatically. Any idea how can i prevent this repositioning in iOS 7?

Answer 1

OK, so I finally got it right.
First of all - Apple does not want us to change position of UINavigationBar. Therefore you should avoid it at all cost. In my case i got an app to fix which moved UINavigationBar to show slide-out menu. The proper solution to slide-out menu problem is to put UINavigationController inside - then you can slide whole UINavigationController with its content (whatever it is) and everything works fine. For some reason UINavigationController was outside in this app. So, i had to resort to a hack. Do not use this method if you have ANY option not to use it. It's a hack, it might break in further iOS versions and Apple would certainly not appreciate it.
First, explore new transitioning system in iOS7: http://www.doubleencore.com/2013/09/ios-7-custom-transitions/
Then, replace:
[self presentViewController:navigationController animated:YES completion:nil];
with
if([UIApplication iOS7]) /* or any other custom iOS7 detection method you implement */
{ /* we simulate old transition with nav bar slided out */
navigationController.transitioningDelegate = [OMModalTransitionDelegate new];
}
[self presentViewController:navigationController animated:YES completion:nil];
So, we need a transition delegate to simulate standard behaviour and do the trick as well.
#import "OMModalTransitionDelegate.h"
#import "OMAnimatedTransitioning.h"
#implementation OMModalTransitionDelegate
- (id <UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source
{
OMAnimatedTransitioning *transitioning = [OMAnimatedTransitioning new];
return transitioning;
}
- (id <UIViewControllerAnimatedTransitioning>)animationControllerForDismissedController:(UIViewController *)dismissed
{
OMAnimatedTransitioning *transitioning = [OMAnimatedTransitioning new];
transitioning.reverse = YES;
return transitioning;
}
#end
And now the actual animation manager (you have to implement sharedBar in a category on UINavigationBar yourself):
static NSTimeInterval const DEAnimatedTransitionDuration = 0.4f;
static NSTimeInterval const DEAnimatedTransitionMarcoDuration = 0.15f;
#implementation OMAnimatedTransitioning
- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
UIViewController *fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
UIView *container = [transitionContext containerView];
UIView *superView = [UINavigationBar sharedBar].superview;
CGRect barFrame = [UINavigationBar sharedBar].frame;
if(self.reverse)
{ /* Trick - first, remove the bar from it's superview before animation starts */
[[UINavigationBar sharedBar] removeFromSuperview];
}
CGRect oldFrame = container.bounds;
if (self.reverse)
{
[container insertSubview:toViewController.view belowSubview:fromViewController.view];
}
else
{
toViewController.view.frame = oldFrame;
toViewController.view.transform = CGAffineTransformMakeTranslation(0, CGRectGetHeight(oldFrame));
[container addSubview:toViewController.view];
}
[UIView animateKeyframesWithDuration:DEAnimatedTransitionDuration delay:0 options:0 animations:^
{
if (self.reverse)
{
fromViewController.view.transform = CGAffineTransformMakeTranslation(0, CGRectGetHeight(oldFrame));
double delayInSeconds = 0.01; /* Trick - after an imperceivable delay - add it back - now it is immune to whatever Apple put there to move it */
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
dispatch_after(popTime, dispatch_get_main_queue(), ^(void)
{
[UINavigationBar sharedBar].frame = barFrame;
[superView addSubview:[UINavigationBar sharedBar]];
});
}
else
{
toViewController.view.transform = CGAffineTransformIdentity;
}
} completion:^(BOOL finished) {
[transitionContext completeTransition:finished];
}];
}
- (NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext
{
return DEAnimatedTransitionDuration;
}
#end

Answer 2

In your custom navigation controller, add
- (void)viewWillLayoutSubviews {
//do your navigation bar layout
}
hope this can help you. Remind, above method only be supported ios >= 5.0.