Book Image

Learning iOS UI Development

Book Image

Learning iOS UI Development

Overview of this book

Through this comprehensive one-stop guide, you’ll get to grips with the entire UIKit framework and in a flash, you’ll be creating modern user interfaces for your iOS devices using Swift. Starting with an overview of the iOS drawing system and the available tools, you will then learn how to use these technologies to create adaptable layouts and custom elements for your applications. Next, you’ll be introduced to other topics such as animation and code-drawing with Core Graphics, which will give you all the knowledge you need to create astonishing user interfaces. By the end of this book, you will have a solid foundation in iOS user interface development and will have gained valuable insights on the process of building firm and complex UIs.
Table of Contents (16 chapters)
Learning iOS UI Development
About the Author
About the Reviewers

Events and touches

The events managed by iOS during user interaction are grouped into three main sets:

  • Multitouch events are generated by the interaction with the screen

  • Motion events are sensed by the accelerometer

  • Remote-control events are mostly originated by external accessories

Even if these events are extremely different, they can be encapsulated and handled by the same class: UIEvent. An event instance can be easily distinguished by checking its type property, a UIEventType enum, with the following declaration:

enum UIEventType : Int {
    case Touches
    case Motion
    case RemoteControl

When users interact with the screen, a multitouch sequence is generated. Each step of a sequence is described by the same UIEvent instance that carries a set of UITouch objects: one per each of the user's fingers taking part in the multitouch sequence.

The event instance remains the same for the whole sequence, and the same is true for the touch instances that are updated during the sequence, preventing...