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
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Gestures and gesture recognizers


Within the methods previously shown, you can perform complex operations and even programmatically filter the touch actions you want to handle, starting from the analysis of UITouch objects. Just to give you an example, you might be able to define that if the touch is constantly moving to the left of the screen in a considerable short amount of time, the user is performing a swipe left action. Identifying multitouch sequences as specific actions using only the UIResponder functions is not trivial, though—especially when it comes to multitouch sequences.

Luckily enough, iOS comes with a number of preset actions that we more appropriately call gestures. A gesture is a way to turn a touch sequence into a specific pattern thanks to algorithms that convert finger movements under the hood into a single specific action.

The set of gestures handled by iOS is somewhat small, but it includes most of the relevant movements you may need for your applications. Here they...