Transparent iOS navigation bar

Question

You can apply Navigation Bar Image like below for Translucent.

Objective-C:

[self.navigationController.navigationBar setBackgroundImage:[UIImage new]
                     forBarMetrics:UIBarMetricsDefault]; //UIImageNamed:@"transparent.png"
self.navigationController.navigationBar.shadowImage = [UIImage new];////UIImageNamed:@"transparent.png"
self.navigationController.navigationBar.translucent = YES;
self.navigationController.view.backgroundColor = [UIColor clearColor];

Swift 3:

self.navigationController?.navigationBar.setBackgroundImage(UIImage(), for: .default) //UIImage.init(named: "transparent.png")
self.navigationController?.navigationBar.shadowImage = UIImage()
self.navigationController?.navigationBar.isTranslucent = true
self.navigationController?.view.backgroundColor = .clear
    

Swift Solution

This is the best way that I've found. You can just paste it into your appDelegate's didFinishLaunchingWithOptions method:

Swift 3 / 4

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    // Override point for customization after application launch.
    // Sets background to a blank/empty image
    UINavigationBar.appearance().setBackgroundImage(UIImage(), for: .default)
    // Sets shadow (line below the bar) to a blank image
    UINavigationBar.appearance().shadowImage = UIImage()
    // Sets the translucent background color
    UINavigationBar.appearance().backgroundColor = .clear
    // Set translucent. (Default value is already true, so this can be removed if desired.)
    UINavigationBar.appearance().isTranslucent = true
    return true
}

Swift 2.0

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
    // Override point for customization after application launch.
    // 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: 0.0, blue: 0.0, alpha: 0.0)
    // Set translucent. (Default value is already true, so this can be removed if desired.)
    UINavigationBar.appearance().translucent = true

    return true
}

source: Make navigation bar transparent regarding below image in iOS 8.1

Swift 5 applying only to the current view controller

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    // Make the navigation bar background clear
    navigationController?.navigationBar.setBackgroundImage(UIImage(), for: .default)
    navigationController?.navigationBar.shadowImage = UIImage()
    navigationController?.navigationBar.isTranslucent = true
}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)

    // Restore the navigation bar to default
    navigationController?.navigationBar.setBackgroundImage(nil, for: .default)
    navigationController?.navigationBar.shadowImage = nil
}

Swift 3 : extension for Transparent Navigation Bar

extension UINavigationBar {
    func transparentNavigationBar() {
    self.setBackgroundImage(UIImage(), for: .default)
    self.shadowImage = UIImage()
    self.isTranslucent = true
    }
}

Swift 4.2 Solution: For transparent Background:

1. For General Approach:

   override func viewDidLoad() {
       super.viewDidLoad()
   
       self.navigationController?.navigationBar.setBackgroundImage(UIImage(), for: UIBarMetrics.default)
       self.navigationController?.navigationBar.shadowImage = UIImage()
       self.navigationController?.navigationBar.isTranslucent = true
   
   }
   

2. For Specific Object:

   override func viewDidLoad() {
       super.viewDidLoad()
   
       navBar.setBackgroundImage(UIImage(), for: UIBarMetrics.default)
       navBar.shadowImage = UIImage()
       navBar.navigationBar.isTranslucent = true
   
   }
   

Hope it's useful.