How to hide UINavigationBar 1px bottom line

Question

I have an app that sometimes needs its navigation bar to blend in with the content.

Does anyone know how to get rid of or to change color of this annoying little ba

Answer 1

I use a UINavigationBar extension that enables me to hide/show that shadow using the UIAppearance API or selecting which navigation bar has to hide/show that shadow using Storyboard (or source code). Here is the extension:

import UIKit

private var flatAssociatedObjectKey: UInt8 = 0

/*
  An extension that adds a "flat" field to UINavigationBar. This flag, when
  enabled, removes the shadow under the navigation bar.
 */
@IBDesignable extension UINavigationBar {
    @IBInspectable var flat: Bool {
        get {
            guard let obj = objc_getAssociatedObject(self, &flatAssociatedObjectKey) as? NSNumber else {
                return false
            }
            return obj.boolValue;
        }

        set {
            if (newValue) {
                let void = UIImage()
                setBackgroundImage(void, forBarPosition: .Any, barMetrics: .Default)
                shadowImage = void
            } else {
                setBackgroundImage(nil, forBarPosition: .Any, barMetrics: .Default)
                shadowImage = nil
            }
            objc_setAssociatedObject(self, &flatAssociatedObjectKey, NSNumber(bool: newValue),
                    objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC)
        }
    }
}

Now, to disable the shadow across all navigation bars you have to use:

UINavigationBar.appearance().flat = true

Or you can enable/disable this behavior using storyboards: