Delay in changing navigationBar.barTintColor in viewWillAppear

Question

I have two view controllers in a navigation controller. I'm trying to change the tint color of the navigation bar for each view controller.

I'm using the following code to accomplish this:

FirstVC:

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(true)
    navigationController?.navigationBar.barTintColor = .yandasRed
    navigationController?.navigationBar.isTranslucent = false
}

SecondVC:

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(true)
    navigationController?.navigationBar.barTintColor = .white
    navigationController?.navigationBar.isTranslucent = true
}

The transition between FirstVC to SecondVC is seemless, and looks great. However when I go back to the FirstVC from the SecondVC, there is a delay in changing the navigation bar tint color. About 1/2 a second.

Why is this? I was under the impression that all code inside viewWillAppear is executed before the view controller is loaded.

Tried the code in the linked question. It crashes the app immediately on loading. I have no understading of how isViewLoaded works, so possibly the code is incomplete? — Alex Ritter, Jan 04 '18 at 18:06

score 3 · Answer 1 · edited Mar 07 '18 at 03:37

3

Based on the answer here, you can implement:

override func willMove(toParentViewController parent: UIViewController?) {
    super.willMove(toParentViewController: parent)
    // Setup your navigation bar
}

I believe this will eliminate the delay.

edited Mar 07 '18 at 03:37

Pang

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answered Mar 07 '18 at 03:07

Nizzam

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Delay in changing navigationBar.barTintColor in viewWillAppear

1 Answers1