Make navigation bar transparent regarding below image in iOS 8.1

Question

I try to set my navigation bar transparent regarding a image below this, something like the following image :

Answer 1

To set this style globally, use the UIAppearance APIs. In AppDelegate's application:didFinishLaunchingWithOptions: add the following code:

// Sets background to a blank/empty image
UINavigationBar.appearance().setBackgroundImage(UIImage(), forBarMetrics: .Default)
// Sets shadow (line below the bar) to a blank image
UINavigationBar.appearance().shadowImage = UIImage()
// Sets the translucent background color
UINavigationBar.appearance().backgroundColor = UIColor(red: 0.0, green: 0.3, blue: 0.5, alpha: 0.3)
// Set translucent. (Default value is already true, so this can be removed if desired.)
UINavigationBar.appearance().translucent = true