Become an iOS app developer—one step at a time. The iOS 10 App Development Essentials series is designed for developers who are new to iOS and want to transition their existing programming skills to Xcode, Swift, and the iOS SDK. Part 3 covers the basics of working with iOS UI controls like picker views, sliders and progress bars, activity indicators, and images views, as well as web views for displaying HTML content. Series author Todd Perkins also shows how to control changes in your layouts (including font size and views) based on device, orientation, or abstract size using size classes, and provides a brief overview of the iOS Human Interface Guidelines.