Erica Sadun - iOS Auto Layout Demystified second Edition

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Second Edition

Erica Sadun

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Library of Congress Control Number: 2013948434

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AirPlay, AirPort, AirPrint, AirTunes, App Store, Apple, the Apple logo, Apple TV, Aqua, Bonjour, the Bonjour logo, Cocoa, Cocoa Touch, Cover Flow, Dashcode, Finder, FireWire, iMac, Instruments, Interface Builder, iOS, iPad, iPhone, iPod, iPod touch, iTunes, the iTunes logo, Leopard, Mac, Mac logo, Macintosh, Multi-Touch, Objective-C, Quartz, QuickTime, QuickTime logo, Safari, Snow Leopard, Spotlight, and Xcode are trademarks of Apple, Inc., registered in the United States and other countries. OpenGL and the logo are registered trademarks of Silicon Graphics, Inc. The YouTube logo is a trademark of Google, Inc. Intel, Intel Core, and Xeon are trademarks of Intel Corp. in the United States and other countries.

ISBN-13: 978-0-321-96719-0
ISBN-10: 0-321-96719-4

Text printed in the United States on recycled paper at RR Donnelley in Crawfordsville, Indiana.

First printing: October 2013

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Hop. Hop. THOOM.

Auto Layout reimagines the way developers create user interfaces. It creates a flexible and powerful system that describes how views and their content relate to each other and to the windows and superviews they occupy. In contrast with older design approaches, this technology offers incredible control over layout, with a wider range of customization than frames, springs, and struts allow. Somewhat maligned by exasperated developers, Auto Layout has gained a reputation for difficulty and frustration, particularly when used through Interface Builder (IB).

Thats why this book exists. Youre about to discover Auto Layout mastery by example, with plenty of explanations and tips. Instead of struggling with class documentation, youll learn in simple steps how the system works and why its far more powerful than you first imagined. Youll read about common design scenarios and discover best practices that make Auto Layout a pleasure rather than a chore to use.

Youll explore many of the strengths of Auto Layout as well. Its a technology that has a lot going for it:

Auto Layout is declarative. You express the interface behavior without worrying about how those rules get implemented. Just describe the layout; let Auto Layout calculate the frames.

Auto Layout is descriptive and relational. You describe how items relate to each other onscreen. Forget about sizes and positions. What matters is the relationships.

Auto Layout is centralized. Whether in IB or a layout section in your own code, Auto Layout rules tend to migrate to a single nexus, making it easier to inspect and debug.

Auto Layout is dynamic. Your interface updates as needed to respond to user- and application-sourced changes.

Auto Layout is localizable. Conquer the world with Auto Layout. Its built to adapt to varying word and phrase lengths while maintaining interface integrity.