Objective-C Programming Nuts and bolts

Objective-C Programming Nuts and Bolts

By Keith Lee

Copyright 2015 Keith Lee

Smashwords Edition

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Objective-C Programming Nuts and Bolts

Motu Presse Publications

No part of this work may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval system, without the prior written permission of the copyright owner and the publisher. No patent liability is assumed with respect to the use of the information contained herein. Although every precaution has been taken in the preparation of this book, the author and publisher assume no responsibility for errors or omissions. Nor is any liability assumed for damages resulting from the use of the information contained herein.

ISBN (electronic): 978-1-4951-7640-1

Every effort has been made to make this book as complete and as accurate as possible, but no warranty or fitness is implied. The information provided is on an as is basis. The author and the publisher shall have neither liability nor responsibility to any person or entity with respect to any loss or damages arising from the information contained in this book.

The source code for examples that accompany this book, as well as other resources, is available at www.motupresse.com.

Table of Contents

Preface

Introduction

Chapter 1: Getting Started

Programming Language

Development Environment

Developer Tools

Your First Objective-C Program

Chapter 2: Key Features

Object Messaging

Encapsulation

Polymorphism

Inheritance

Dynamic Runtime

Memory Management

Chapter 3: Application Structure

Preprocessor Elements

Variables

The Class Section

Properties

Methods

The Main Section

C Language Elements

Chapter 4: Basic Elements

Variables

Comments

Other Types

Operators

Expressions and Statements

Chapter 5: Objective-C Literals

NSNumber Literals

Container Literals

Expression Literals

Object Subscripting

Chapter 6: Blocks

Syntax

Usage

Block Objects

Chapter 7: Generics

Syntax

Usage

Chapter 8: Additional Topics

Understanding Variable Scope

Using NULL, nil, and NSNull

String Constants versus String Literals

MRR Memory Management

ARC Memory Management

Understanding Properties

Using Categories

Message Selectors

Forwarding Declarations

Handling Errors

Concurrent Programming

NSObject Methods

Chapter 9: Frameworks and Services

Cocoa and Cocoa Touch

Foundation Framework

Chapter 10: Resources

Chapter 11: NeXT Steps

About the Author

Preface

Objective-C Programming Nuts and Bolts provides a clear and concise overview of the programming language, describes its key features and APIs, and presents recommendations for developing iOS, watchOS, and OS X programs using Objective-C. Very quickly, the reader will have a solid understanding of Objective-C and be ready to begin using it on his/her projects.

So, let’s begin!

INTRODUCTION

Objective-C is one of the standard programming languages for developing applications on Apple’s iOS, watchOS, and OS X platforms. In recent years these platforms have become some of the most popular development environments for programmers. General users and IT professionals alike want to be able to quickly grasp the fundamentals of this technology and begin using it to build solutions. This book was written to help you acquire this knowledge by answering the following questions: 1) What do you need to know to understand the Objective-C language and its role within the Apple technology ecosystem?, 2) what do you need to begin developing programs using Objective-C, and 3) how do you quickly transition to Objective-C from another programming language? Objective-C Programming Nuts and Bolts provides these answers.

Who This Book Is For

This book is for developers of all levels of expertise who have, at a minimum, knowledge of basic programming concepts. In addition knowledge of object-oriented programming concepts, while not necessary, is also useful.

What You Need

Before you begin writing Objective-C code for the Apple platforms, you’ll need an Intel-based Mac computer running OS X El Capitan (version 10.11) or later. You’ll also need Xcode 7 (or later), Apple’s toolset for software development using Objective-C.

How to Use This Book

This book is divided into three parts. Part One provides an introduction to object-oriented programming with Objective-C, describes the software development environment for the iOS, watchOS, and OS X platforms, and summarizes key features of the language. Part Two is more focused on application development - it features an in-depth look at the principal components of Objective-C programs, along with a detailed review of the key frameworks and services used for Objective-C application development. Part Three consists of final comments on this book along with references and recommendations that will be useful as you develop apps using Objective-C.

Readers who want a general understanding of Objective-C technology on the Apple platforms will probably focus more on Part One of the book (Chapters 1-2). Experienced developers looking to transition to Objective-C will tend to concentrate on Part Two (Chapters 3-9).

Typographical Conventions

The following typographical conventions are used in this book:

Bold font style within the body of text indicates significant words or phrases. Bold is also used to identify chapters or sections within a chapter.

Italics font style indicates new words or phrases that are explained further in the body of the book.

Monospaced, constant width font is used for programming code excerpts and examples.

Monospaced, constant width bold font is used within programming code excerpts and examples to indicate key elements and concepts.

Monospaced, constant width italic font is used within programming code excerpts to indicate comments.

Attention New Programmers!

Particularly for beginners, computer programming can be a little frustrating at first. Here are a few recommendations that will be very helpful when you start writing programs:

Proper syntax - It is very important that your program code has the correct syntax. Specifically, capitalization, spacing, and other syntax elements should be identical to that shown in this book and the reference documentation. In general computers and programming languages are very strict about syntax, so if you make typing errors your program will not run properly.

Check your work – Mistakes happen, so check your work frequently, particularly just before you run your programs.

One step at a time – Develop your programs incrementally. This means write small portions of code, test and fix errors until you verify the code works as expected, and add more code to your program accordingly.

GETTING STARTED

How do you get started with a new programming language? The first steps include acquiring a basic understanding of the language and its key features, along with knowledge of the infrastructure, facilities and tools available for software development. We'll start to lay this foundation here.

Programming Language

Brad Cox and Tom Love created the Objective-C programming language in the early 1980s, with the primary goal of adding object-oriented extensions to the ANSI C programming language. Objective-C is actually a strict superset of C that has been extended with features to support object-oriented programming. These features (object orientation, dynamic types, and reflection) were derived from the Smalltalk programming language.

In 1996 Apple acquired NeXT Software; the NeXTstep/OPENSTEP system served as the basis for the current Apple operating system (OS X). NeXTstep also provided built-in support for the Objective-C language.

Over the years Apple has released many new features to Objective-C to make programming with the language faster, safer, and more efficient. Some latest updates include automatic memory management, declared and synthesized properties, fast enumeration, exception support, performance enhancements, 64-bit machine support, and support for generic programming. You will learn about these and many other features in the upcoming features.