Programmatically get height of navigation bar

Question

I know that the presence of the more view controller (navigation bar) pushes down the UIView by its height. I also know that this height = 44px. I have also discovered tha

Answer 1

My application has a couple views that required a customized navigation bar in the UI for look & feel, however without navigation controller. And the application is required to support iOS version prior to iOS 11, so the handy safe area layout guide could not be used, and I have to adjust the position and height of navigation bar programmatically.

I attached the Navigation Bar to its superview directly, skipping the safe area layout guide as mentioned above. And the status bar height could be retrieved from UIApplication easily, but the default navigation bar height is really a pain-ass...

It struck me for almost half a night, with a number of searching and testing, until I finally got the hint from another post (not working to me though), that you could actually get the height from UIView.sizeThatFits(), like this:

- (void)viewWillLayoutSubviews {
    self.topBarHeightConstraint.constant = [UIApplication sharedApplication].statusBarFrame.size.height;
    self.navBarHeightConstraint.constant = [self.navigationBar sizeThatFits:CGSizeZero].height;

    [super viewWillLayoutSubviews];    
}

Finally, a perfect navigation bar looking exactly the same as the built-in one!