Navigation bar height animation

Question

Created Oct ’16

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Hi,

I've a simple UINavigationController with a root view controller having a prompt set in it's navigation item. When a second view controller is pushed without a prompt, the animation runs in two steps.

The second view controller is moved in from the right, while the navigation bar height stays the same.
The navigation bar height is animated to the smaller height because the space for the prompt is no longer needed.

So far so good.

What I want to achieve is having a UIView placed right below the navigation bar. So it first have to be at Y=74, which is the height of the navigation bar with prompt. And while the navigation bar shrinks I would like to animate Y position of the view to 44, which is the height of the bar without prompt.

I don't use autolayout, so if there's a solution using constraints, it doesn't work for me.

For some reason viewDidLayoutSubviews is not called at all. Well, only the first time the view controller is pushed.

Is there any way to achieve what I've described?

Dirk

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Answer 1

Frameworks Engineer OP

Apple

Oct ’16

You don't necessarily need constraints, but you do need to look at the topLayoutGuide inside of your view controller's -viewWillLayoutSubviews or -viewDidLayoutSubviews method.

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Answer 2

just.do.it OP

Jul ’17

I would love to do so, but iOS10 doesn't call neither viewWillLayoutSubviews no viewDidLayoutSubviews.

In iOS11 both the animation has changed (it's now all done in one single push view controller and shrink brar animation) and viewWillLayoutSubviews / viewDidLayoutSubviews is called.

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