iOS Auto Layout Demystified

Auto Layout re-imagines the way developers create user interfaces. It provides 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 to older design approaches, this technology offers incredible control over layout with a wider range of customization than frames, springs, and struts can express. In this guide, Erica Sadun, bestselling author of The Core iOS 6 Developer's Cookbook and The Advanced iOS 6 Developer's Cookbook, helps readers learn how to use Auto Layout effectively, even masterfully, by providing an abundance of examples alongside plenty of explanations and tips. Instead of struggling with class documentation, you learn in simple steps how the system works and why it’s far more powerful than you first imagined. You read about common design scenarios and discover best practices that make Auto Layout a pleasure rather than a chore to use. Sadun includes examples of non-obvious ways to use Auto Layout to build interactive elements, animations, and other features beyond what you might normally lay out in Interface Builder to help expand the reader’s design possibilities. With this book you will learn The basic concepts that form the foundation of Auto Layout How to create clear and satisfiable rules of your layout, called constraints How to work effectively with the Interface Builder Layout What visual constraints look like, how to work with them, and how they are used in your projects How to debug constraints How to design interfaces when working with Auto Layout Effective solutions to the most common real-world problems and challenges Approximately 238 pages. For related content by author Erica Sadun, see The Core iOS 6 Developer’s Cookbook, and The Advanced iOS 6 Developer’s Cookbook.

Table of Contents:
Preface Chapter 1: Introducing Auto Layout Saying “No” to Auto Layout Saying “Yes” to Auto Layout              Visual Relationships              Content-Driven Layout              Prioritizing Rules              Auto Layout Strengths Constraints              Satisfiability              Sufficiency Constraint Attributes Missing Views              Underconstrained Missing Views              Missing Views with Inconsistent Rules              Tracking Missing Views Ambiguous Layout              Exercising Ambiguity              Visualizing Constraints Intrinsic Content Size Compression Resistance and Content Hugging Auto Layout and Frames              Visualizing Alignment Rectangles              Image Alignment Insets              Declaring Alignment Rectangles              Implementing Alignment Rectangles Summary Chapter 2: Constraints Constraint Types Priorities              Conflicting Priorities              Enumerated Priorities Content Size Constraints              Content Hugging              Compression Resistance              Setting Content Size Constraints Layout Constraints              Constraint Math The Layout Constraint Class              First and Second Items Creating Layout Constraints Using NSLayoutConstraint              Unary Constraints              Zero-Item Constraints View Items Constraints, Hierarchies, and Bounds Systems Installing Constraints Removing Constraints Comparing Constraints              Using Matched Constraints Laws of Layout Constraints Summary Chapter 3: Interface Builder Layout Constraints in Interface Builder              What’s What in the IB Editor              Beginning Constraints Constraint Listings              Constraint Colors              Constraint Icons              Constraint Listings and Xcode Labels              Adding Xcode Identities Selecting Constraints Inspecting Constraints              The Constraint Attributes Inspector View Size Inspector              Frame and Layout Rectangles              Constraint Options Adding User Constraints              Including Your Own Constraints              Conflicting Constraints Building New Constraints The Missing Views Problem Balancing Requests              Balancing Constraint Priorities Constraints and Outlets Hybrid Layout              Building a NIB File for Testing              Adding the NIB File in Code              Advantages of Hybrid Layout Constraints/Resizing Pop-Up Menu Summary Chapter 4: Visual Formats Introducing Visual Format Constraints Options              Alignment              Combining Options              Skipping Options Variable Bindings              The Problem with Indirection              Indirection Workaround Metrics              Real-World Metrics Format String Structure Orientation              Retrieving Constraints by Axis View Names              Superviews Connections              Empty Connections              Standard Spacers              Numeric Spacers              Referencing the Superview              Spacing from the Superview              Flexible Spaces              Parentheses              Negative Numbers              Priorities              Multiple Views View Sizes Format String Components Getting It Wrong NSLog and Visual Formats Constraining to a Superview View Stretching Constraining Size Building Rows or Columns Matching Sizes Why You Cannot Distribute Views              How to Pseudo-Distribute Views (Part 1: Equal Centers)              Pseudo-Distributing Views (Part 2: Spacer Views) Summary Chapter 5: Debugging Constraints Reading Console Logs              Example: Autosizing Issues              Solution: Switch Off Autosizing Translation              Example: Auto Layout Conflicts              Solution: Adjusting Priorities              The Nuclear Approach              The Balance Approach              Tracing Ambiguity Examining Constraint Logs              Example: Alignment Constraint              Example: Standard Spacers              Example: Equation-Based Constraint              Example: Complex Equation              Example: The Multiplier and Constant A Note about Layout Math Constraint Equation Strings Adding Names              Using Nametags              Naming Views Describing Views Example: Unexpected Padding Example: The Hugged Image Example: View Centering              Retrieving Referencing Constraints Descent Reports Example: Ambiguity Example: Expanding on Console Dumps Visualizing Constraints              Automating Visualization Launch Arguments Internationalization              Doubled Strings              Flipped Interfaces (OS X)              Flipped Interfaces (iOS) Profiling Cocoa Layout Auto Layout Rules of Debugging Summary Chapter 6: Building with Auto Layout Basic Principles of Auto Layout Layout Libraries Planning Interfaces Building for Modularity Updating Constraints              Calling Updates and Animating Changes              Animating Constraint Changes on OS X              Fading Changes Handling Orientation-Specific Text Layout Designing for Edge Conditions Building a View Drawer              Building the Drawer Layout              Managing Layout for Dragged Views              Dragged Views Window Boundaries Summary Chapter 7: Layout Solutions Table Cells Preserving Image Aspect Accordion Sizing Auto Layout              Building a Paged Image Scroll View              Inherent Drawbacks Centering View Groups Custom Multipliers and Random Positions Building Grids Constraint Animation on Steroids Summary