Animating a navigation bar color

Question

I am trying to animate a change of color of a navigation bar when popping back to a previous controller. To give it some context, I have controller A which is a collectionVi

Answer 1

Details

xCode 8.3.2, swift 3.1

Solution

override func viewWillAppear(_ animated: Bool) {
    if let navigationBar = self.navigationController?.navigationBar {
        navigationBar.backgroundColor = .blue
    }
}

Full sample

ViewController

import UIKit

class ViewController: UIViewController {

    override func viewWillAppear(_ animated: Bool) {
        if let navigationBar = self.navigationController?.navigationBar {
            navigationBar.barTintColor = UIColor(red: 244/255, green: 67/255, blue: 54/255, alpha: 1.0)
            navigationBar.tintColor = .white
            navigationBar.titleTextAttributes = [NSForegroundColorAttributeName : UIColor.white]
            navigationBar.isTranslucent = false
        }
    }
}

ViewController2

import UIKit

class ViewController2: UIViewController {

    override func viewWillAppear(_ animated: Bool) {
        if let navigationBar = self.navigationController?.navigationBar {
            let color = UIColor(red: 1, green: 153/255, blue: 0, alpha: 1.0)
            navigationBar.setBackgroundImage(UIImage.imageWithColor(color: color), for: .default)
            navigationBar.shadowImage = UIImage()
            navigationBar.isTranslucent = true
        }
    }

    override func viewWillDisappear(_ animated: Bool) {
        if let navigationBar = self.navigationController?.navigationBar {
            navigationBar.setBackgroundImage(nil, for: .default)
            navigationBar.shadowImage = nil
            navigationBar.isTranslucent = false
        }
    }
}

extension UIImage

import UIKit

extension UIImage {
    class func imageWithColor(color: UIColor) -> UIImage {
        let rect = CGRect(x: 0, y: 0, width: 1, height: 1)
        UIGraphicsBeginImageContextWithOptions(CGSize(width: 1, height: 1), false, 0)
        color.setFill()
        UIRectFill(rect)
        let image = UIGraphicsGetImageFromCurrentImageContext()!
        UIGraphicsEndImageContext()
        return image
    }
}

Main.storyboard