Transparent navigation bar snippet

Put this code into viewDidLoad method of a view controller where you want to have transparent navigation bar.

Swift 3.0

navigationController?.navigationBar.setBackgroundImage(UIImage(), for: .default)
navigationController?.navigationBar.shadowImage = UIImage()
navigationController?.navigationBar.isTranslucent = true
navigationController?.view.backgroundColor = UIColor.clear

navigationController?.navigationBar.setBackgroundImage(UIImage(), for: .default)

navigationController?.navigationBar.shadowImage = UIImage()

navigationController?.navigationBar.isTranslucent = true

navigationController?.view.backgroundColor = UIColor.clear

Objective-C

[self.navigationController.navigationBar setBackgroundImage:[UIImage new]
                     forBarMetrics:UIBarMetricsDefault]; 
self.navigationController.navigationBar.shadowImage = [UIImage new];
self.navigationController.navigationBar.translucent = YES;
self.navigationController.view.backgroundColor = [UIColor clearColor];