iOS navigation bar bottom line is missing

Question

I makes the navigation bar completely transparent by adding the following codes in viewWillAppear:

self.navigationController?.navigationBar.setBackgroundImage(UIImage(), forBarMetrics: UIBarMetrics.Default)
self.navigationController?.navigationBar.shadowImage = UIImage()
self.navigationController?.navigationBar.translucent = true
self.navigationController?.navigationBar.barStyle = UIBarStyle.Black

Before the current view disappear, I reset the navigation bar by doing this in the viewDidDisappear method:

self.navigationController?.navigationBar.setBackgroundImage(nil, forBarMetrics: UIBarMetrics.Default)
self.navigationController?.navigationBar.shadowImage = nil

but it turns out the little bottom line of the navigation bar is missing, here is the image that shows the normal navigation bar:

but it turns out being like this:

any idea about what is going on? and any solutions? thanks

Answer 1

it's missing because you set shadow image to nil. To fix this, delete line below :

self.navigationController?.navigationBar.shadowImage = nil