Imitate iOS 7 Safari Nav-Bar

Question

In iOS7 the navigationBar in Safari automatically shrinks when scrolling. So does the navigationBar in Facebook, even to a point where it completely vanishes.

How would you implement this behavior yourself? I guess you would also have to dynamically adjust the contentOffset and I guess that would also collide with the default Refresh Control, wouldn't it?

Ask on the internal Apple forums, probably a better place to get the answer. If you get it answer your own question as others are surely interested. — David H, Oct 19 '13 at 12:31
Also, look at this answer - how to animate the bar open and closed: http://stackoverflow.com/a/2079655/1633251 — David H, Oct 19 '13 at 15:35
@DavidH that unfortunately doesn't help me. I dont want to hide the navigationbar in one go, i want it to change while people are scrolling and depending on how much they scrolled. — Infinite, Oct 19 '13 at 16:49
Right. So using gesture recognizers and monitoring scroll view delegate messages you open and close it at various times. That code you will have to write yourself. — David H, Oct 20 '13 at 12:21
You can get the code to handle the scrolling behavior here : http://stackoverflow.com/questions/19819165/imitate-ios-7-facebook-hide-show-expanding-contracting-navigation-bar It's not as clean as Safari behavior but it's a start. — CedricSoubrie, Jan 31 '14 at 11:35
Related .. http://stackoverflow.com/questions/19819165/imitate-ios-7-facebook-hide-show-expanding-contracting-navigation-bar — Fattie, Feb 28 '14 at 20:43

score 0 · Answer 1 · answered Jan 18 '14 at 11:49

That's not right way of doing this, but it worked for me. I created category on UINavigationBar and overrode sizeThatFits: there like this:

- (CGSize)sizeThatFits:(CGSize)size
{
    CGSize cSize = self.frame.size;
    BOOL isPortrait = UIInterfaceOrientationIsPortrait([[UIApplication sharedApplication] statusBarOrientation]);
    CGFloat originalHeight = isPortrait ? 44: 32;
    cSize.height = self.tag > 0 ? originalHeight / 2 : originalHeight;
    return cSize;
}

Then when I need to shrink navigation bar (in scroll view's delegate methods):

CGRect navBarFrame = self.navigationController.navigationBar.frame;
BOOL isPortrait = UIInterfaceOrientationIsPortrait(self.interfaceOrientation);
CGFloat originalHeight = isPortrait ? 44: 32;
navBarFrame.size.height = expand ? originalHeight : originalHeight / 2;
self.navigationController.navigationBar.tag = expand ? 0 : 1;
[UIView animateWithDuration:0.25 animations:^{
    self.navigationController.navigationBar.frame = navBarFrame;
    [self.navigationController.view setNeedsLayout];
}

Also, you may want to hide navigation items (like UIBarButtonItems) inside animation.

Imitate iOS 7 Safari Nav-Bar

1 Answers1