Sams Teach Yourself Objective-C in 24 Hours > Hour 12. Routing Messages with Selectors > Workshop

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Sams Teach Yourself Objective-C in 24 Hours

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Table of Contents

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Introduction

Part I. Getting Started with Objective-C

Part II. Working with the Objective-C Basics

Hour 6. Exploring Messaging and a Testbed App

Hour 7. Declaring a Class in an Interface File

Hour 8. Declaring Instance Variables in an Interface File

Hour 9. Declaring Properties in an Interface File

Hour 10. Declaring Methods in an Interface File

Hour 11. Declaring Actions in an Interface File

Hour 12. Routing Messages with Selectors

Getting Inside Objective-C Messages

Getting Inside the Objective-C Runtime

Working with SEL and @selector ()

Using performSelector

Using NSInvocation

Testing Whether an Instance Can Respond to a Selector

Summary

Q&A

Workshop

Hour 13. Building on the Foundation

Hour 14. Defining a Class in an Implementation File

Hour 15. Organizing Data with Collections

Hour 16. Managing Memory and Runtime Objects

Part III. Expanding and Extending Classes

Part IV. Beyond the Basics

Part V. Appendixes

Index

Workshop

Quiz

1. How do you make certain that a message you are sending is valid?

2. NSInvocation converts an Objective-C message to what?

Quiz Answers

1. Package it in a selector and test it against the receiver with respondsToSelector.

2. An object.

Activities

Explore the sample code on developer.apple.com to see how you can use selectors. Good choices are the following:

• NSInvocation—CubePuzzle (Mac OS X), GeocoderDemo (iOS)

• performSelector—QuickLookSketch (Mac OS X), WorldCities (iOS)

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