Remove custom subview in navigation bar added from controller

Question

I am adding a custom subview into the navigation bar from a view controller like so (width is derived at layout from the button's contentMode = .scaleAspectFit):

// navigationBar is just sugar for navigationController.navigationBar
navigationBar?.addSubview(button)
button.centerYAnchor.constraint(equalTo: navigationBar!.centerYAnchor).isActive = true
button.leftAnchor.constraint(equalTo: navigationBar!.leftAnchor, constant: navigationBar!.bounds.size.width / 18).isActive = true
button.heightAnchor.constraint(equalTo: navigationBar!.heightAnchor, multiplier: 0.5).isActive = true

In my viewDidDisappear I attempted to do a button.removeFromSuperview() but ended up with a crash:

Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Cannot modify constraints for UINavigationBar managed by a controller'

which I have trouble to understand. I have tried tagging the button and removing it from a UINavigationControllerDelegate without success.

Is there something I am doing fundamentally wrong?

Thanks in advance.

Possible duplicate of [Adding autolayout constraints to navigation controller programatically](https://stackoverflow.com/questions/28708074/adding-autolayout-constraints-to-navigation-controller-programatically) — DonMag, Jul 13 '17 at 16:36

score 3 · Answer 1 · edited Aug 30 '18 at 20:58

3

First make all constraints inactive and remove from superview,

override func viewDidDisappear(_ animated: Bool) {
    button.constraints.forEach { $0.isActive = false }
    button.removeFromSuperview()
}

edited Aug 30 '18 at 20:58

Elijah

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answered Jul 14 '17 at 11:25

Manikanta Chintapalli

323
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score 3 · Answer 2 · answered Oct 02 '18 at 10:43

At my case removing constraints worked like a charm. Note: I used from snapKit. And before removing navigationBar's subview I removed all constraints from this subview.

for instance:

someSubview.snp.removeConstraints()
someSubview.removeFromSuperview()

That is all.

Remove custom subview in navigation bar added from controller

2 Answers2