Customizing Appearance of iOS Composite Controls

An example of a "composite control" is a Search Bar.
If you want to customize one of the controls in the composite control and there is no direct property for it, then you can use the UIAppearance protocol that controls implement.

Example

 
let textfieldsInSearchBars = UITextField.appearance
    (whenContainedInInstancesOf: [UISearchBar.self])
textfieldsInSearchBars.tintColor = .lightGray
textfieldsInSearchBars.backgroundColor = .darkGray
textfieldsInSearchBars.textColor = .lightGray
 

(Swift 3)