What is UI in iPhone?
UI elements are the visual elements that we can see in our applications. Some of these elements respond to user interactions such as buttons, text fields and others are informative such as images, labels.
Who designed iOS UI?
The Introduction of the iPhone,
During this period, Scott Forstall was the lead iOS UI designer. The iPhone's UI had a complete skeuomorphic style; meaning UI features were designed to resemble real-life items. Gradients, drop-shadow and borders were added to buttons to make them seem 3D and clickable.