Objective-C Memory Management Essentials

Gibson Tang, Maxim Vasilkov

• Publisher: Packt Publishing
• Year: 2015
• eBook ISBN: 9781849697132
• Topic: Computer Science
• Subtopic: Programming
• Index: Computer Science

About This Book

• Learn about the concepts of memory management in Objective-C
• Get introduced to Swift, an innovative new programming language for Cocoa and Cocoa Touch
• A step-by-step approach to various memory management techniques with lots of sample code and Xcode projects for your reference

Who This Book Is For

If you are new to Objective-C or a veteran in iOS application development, this is the book for you. This book will ensure that you can actively learn the methods and concepts in relation to memory management in a more engaging way. Basic knowledge of iOS development is required for this book.

Objective-C Memory Management Essentials

---

Table of Contents

Objective-C Memory Management Essentials

Credits

About the Authors

About the Reviewers

www.PacktPub.com

Support files, eBooks, discount offers, and more

Why subscribe?

Free access for Packt account holders

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Errata

Piracy

Questions

1. Introduction to Objective-C Memory Management

Why do we need memory management in Objective-C?

An object's ownership and life cycle

Ownership of object and reference counting

What's a memory leak and why pay attention to it?

What is an object within Objective-C?

Summary

2. Automatic Reference Counting

What is ARC and how does it work?

How ARC looks

Project settings for ARC

A memory model in Objective-C

What you need to know about ARC and weak references

Summary

3. Using Autorelease Pools

Understanding the autorelease pool mechanism

Autorelease pool mechanism

Reducing peak memory footprint with autorelease pool blocks

An overview of Apple autoreleased classes

NSRunLoop

NSException

ARC and autorelease

Autorelease pool blocks and threads

Summary

4. Object Creation and Storage

Creation and initialization of objects

What is a class?

Classes

Object immutability

Object mutability

Inheritance

Convenience initializers

An Objective-C programmer's responsibility

The singleton pattern

Creating @property

Creating custom methods

String formatting

Summary

5. Managing Your Application Data

Device memory

Image optimization

Lazy loading

Control creation

Caching

SDWebImage

Object serialization

SQLite

SQLite versus Core Data

Summary

6. Using Core Data for Persistence

Why use Core Data?

Understanding Core Data concepts

Putting it into practice

Getting into the code

Saving data into the persistent store

Deleting data from the persistent store

Updating data

Summary

7. Key-value Programming Approaches

What is key-value coding or KVC?

The NSKeyValueCoding protocol

Compliance of attributes and one-to-one relationships

Compliance of indexed one-to-many relationships

Compliance of unordered many-to-many relationships

Advantages of key-value coding

Disadvantages of key-value coding

Manual subsets of NSKeyValueCoding behavior

Advantages of creating your own lookup path

Disadvantages of creating your own lookup path

Associated objects

Advantages of using associated objects

Disadvantages of using associated objects

Selectors as keys

Advantages of using selectors as keys

Disadvantages of using selectors as keys

Maximum flexibility and handling unusual keys/values

Advantages of doing your own implementation

Disadvantages of doing your own implementation

Key-value observing

Implementing key-value observing

Performance considerations

Summary

8. Introduction to Swift

Welcome to Swift

Basics of Swift

Variable declaration

Iterating statements

Conditional statements

Functions

Classes and structures in Swift

Closures

Memory management in Swift

Summary

9. Memory Management and Debugging

Memory leaks

Strong/weak references

Retain cycles

Memory overuse

Using the debugger and breakpoints

Collecting data on your app

Plumbing memory leaks

Using the LLVM / Clang Static Analyzer

Using NSZombie

Summary

10. Tips and Tricks for Memory Management

Objective-C, C, and memory management

Getters and setters

The property attribute in Objective-C

Performance guidelines

Don't overthink about memory management

When to avoid KVC and KVO

Summary

11. Features of Xcode 6

Introducing Xcode 6

What's new in storyboard

Allowing storyboard or the NIB file to replace launch images

Launching images from your app

Universal storyboards

Debugging in Xcode 6

Debug gauges

What's new in Interface Builder

Playground for Swift

Summary

Index

Objective-C Memory Management Essentials

Copyright © 2015 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the authors, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

First published: March 2015

Production reference: 1190315

Published by Packt Publishing Ltd.

Livery Place

35 Livery Street

Birmingham B3 2PB, UK.

ISBN 978-1-84969-712-5

www.packtpub.com

Credits

Authors

Gibson Tang

Maxim Vasilkov

Reviewers

Emil Atanasov

Christine M. Gerpheide

Commissioning Editor

James Jones

Acquisition Editor

James Jones

Content Development Editor

Amey Varangaonkar

Technical Editor

Vijin Boricha

Copy Editor

Janbal Dharmaraj

Project Coordinator

Leena Purkait

Proofreaders

Simran Bhogal

Maria Gould

Indexer

Hemangini Bari

Graphics

Sheetal Aute

Production Coordinator

Melwyn D'sa

Cover Work

Melwyn D'sa

About the Authors

Gibson Tang grew up loving technology after getting his hands on an old Apple II when he was still a young kid. Since then, he has never stopped keeping pace with technology, and after he coded his first "Hello World" program, he has been hooked on programming ever since.

Following his studies at Nanyang Polytechnic and Singapore Institute of Management and serving a 6-year stint in the Republic of Singapore Navy (RSN), he honed his development skills creating software and games for Yahoo! and other Fortune 500 companies. In 2010, he founded Azukisoft Pte Ltd in Singapore to focus on mobile application development. Since then, he has developed countless mobile applications and games for start-ups and big companies both in USA and Singapore.

Apart from programming, he indulges in various hobbies such as soccer, computer games, and jogging in order to get his regular dose of Vitamin D and to see the sun once in a while. Occasionally, he would be on Steam or Battle.net blowing off some steam by slaying monsters and killer robots after a day of programming.

I would like to thank the many people who have contributed to my knowledge of programming over the years. Some honorable mentions go out to the geeks and nerds of Hackerspace.sg as they have kept me in stitche...

Table of contents

• Objective-C Memory Management Essentials