iOS Programming Cookbook: Over 50 exciting and powerful recipes to help you unearth the promise of iOS programming

iOS Programming Cookbook

Over 50 exciting and powerful recipes to help you unearth the promise of iOS programming

Hossam Ghareeb

BIRMINGHAM - MUMBAI

iOS Programming Cookbook

Copyright © 2017 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 author, 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 2017

Production reference: 2310317

Published by Packt Publishing Ltd.

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ISBN 978-1-78646-098-1

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Credits

About the Author

Hossam Ghareeb is a software engineer who graduated from Alexandria University in 2012. He found his passion in mobile development, especially iOS development. Currently, he is a senior iOS developer at Noon e-commerce in Dubai.

Hossam has built his experience by learning tips and tricks from the managers he works with, open source projects, and online tutorials. He discovered that the best way to pay this back is to share his experience with others and help people get experience in iOS development.

First of all, big thanks to my parents whom I owe for everything I have and the good things that they taught me. I would like to thank my wife for her support and encouragement to keep writing the book. I want to thank my son Yusuf for inspiring me despite of all the time this took me away from him. Thanks to all the mentors that I've met over the years. Last but not least, special thanks to Samantha Gonsalves, the content editor of the book, for her cooperation and support in completing the book and to the reviewers for their comments and suggestions.

About the Reviewer

Siddharth Shekar is a game developer with over 5 years of industry experience in game development, 11 years of experience in C++, C#, and other programming languages, and is adept at graphics libraries and game engines such as Unity and Unreal. He has also published games on the iOS, Android, Amazon, and Windows Phone App Stores.

Siddharth is also the author of Learning Cocos2d-x Game Development, Learning iOS 8 Game Development Using Swift, and Cocos2d Cross-Platform Game Development Cookbook, all published by Packt Publishing.

Currently, he is a lecturer in the Games Department at Media Design School, Auckland, New Zealand. He teaches graphics programming and PlayStation 4/PS Vita native game development and mentors final year production students.

More information about Media Design School and Siddharth Shekar can be found at www.mediadesignschool.com.

I would like to thank my parents for supporting me in everything that I choose to do. I would also like to thank Media Design School for encouraging me to continue working on this book. Finally, I would like to thank Packt Publishing for putting this book together and offering me the opportunity to review the book.

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Table of Contents

Preface

What this book covers

What you need for this book

Who this book is for

Sections

Getting ready

How to do it...

How it works...

There's more...

See also

Conventions

Reader feedback

Customer support

Downloading the example code

Downloading the color images of this book

Errata

Piracy

Questions

Swift Programming Language

Introduction

Using closures to create self-contained code

Getting ready

How to do it...

How it works...

There's more...

Inferring type

Omitting the return keyword

Shorthand arguments

Creating enumerations to write readable code

Getting ready

How to do it...

How it works...

There's more...

Enum raw values

Assigning raw values

Using Enums with raw values

Enums with associated values

Working with protocols and delegates

Getting ready

How to do it...

How it works...

There's more...

Mutating methods

Delegation

Class-only protocols

Checking protocol conformance

Optional requirements

Using extensions to extend classes functionality

Getting ready

How to do it...

How it works...

There's more...

Mutating instance methods

Adding new initializer

Define subscripts

Working with memory management and ARC

Getting ready

How to do it...

How it works...

There's more...

Using error handling

Getting ready

How to do it...

How it works...

There's more...

Multiple catch statements

Disable error propagation

Using generics to write generic and reusable code

Getting ready

How to do it...

How it works...

The Essentials

Introduction

Using UIView via code or interface builder to build your own custom views

Getting ready

How to do it...

How it works...

There's more...

Working with navigation controller and navigation bar

Getting ready

How to do it...

How it works...

There's more...

Push and pop

Hiding navigation bar

Navigation bar color

Working with stack views

How to do it

How it works...

Working with UICollectionView

How to do it...

How it works...

There's more...

Customizable layouts

Working with gestures like swipe, pan, rotation, and tap

Getting ready

How to do it...

How it works...

There's more...

Using 3D touch

How to do it...

How it works...

There's more...

Home screen quick actions

Integrating with Messages App

Introduction

Integrating iMessage app with sticker pack

Getting ready

Stickers

How to do it...

How it works...

There's more...

Integrating iMessage app with iMessage app

Getting ready

How to do it...

How it works...

There's more...

Showing progress indicator

Request files with pagination

Working with Interface Builder

Introduction

Using storyboards

Getting ready

How to do it...

How it works...

There's more...

Segues attributes

Preparing for a segue

Unwind segues (exit segues)

Custom segues

Working with Autolayout and constraints

Getting ready

How to do it...

How it works...

There's more...

Updating constraints

Designing your interface builder for any size classes in one storyboard

Getting ready

How to do it...

How it works...

Embedding view controllers using container view

How to do it...

How it works...

There's more...

Working with UITableView

Introduction

Working with scroll view

Getting ready

How to do it...

How it works...

There's more...

Using TableView sections, headers and footers

Getting ready

How to do it...

How it works...

There's more...

Custom section header and footer

Using custom cells

Getting ready

How to do it...

How it works...

Resizing table view cells dynamically

How to do it...

How it works...

Editing table views

Getting ready

How to do it...

Inserting cells with animation

Removing cells with animation

Dragging and dropping to reorder cells

How it works...

There's more...

Animations and Graphics

Introduction

Drawing text, images, lines, rectangles, and gradients

Getting ready

How to do it...

How it works...

There's more...

Animating shapes drawn with UIBezierPath

Getting ready

How to do it...

How it works...

Animating UIViews

How to do it...

How it works...

Multimedia

Introduction

Working with audio capabilities

Getting ready

How to do it...

How it works...

There's more...

Recognizing speech

Playing videos

Getting ready

How to do it...

How it works...

There's more...

Slide Over

Split View

Picture-in-Picture

Capturing photos and videos

How to do it...

How it works...

Using filters with CoreImage

How to do it...

How it works...

Concurrency

Introduction

Using Dispatch queues

Getting ready

How to do it...

How it works...

There's more...

Using Operation queues

Getting ready

How to do it...

How it works...

Using Operation subclassing

How to do it...

How it works...

Location Services

Introduction

Detecting user location

How to do it...

How it works...

Displaying pins in map view

Getting ready

How to do it...

How it works...

Getting directions between locations

How to do it...

How it works...

Working with geofencing

How to do it...

How it works...

Security and Encryption

Introduction

Using Touch ID for user authentication

Getting ready

How to do it...

How it works...

Working with Keychain

Getting ready

How to do it...

How it works...

Encryption

Getting ready

How to do it...

How it works...

Networking

Introduction

Using NSURLSession API for network connections

Getting ready

How to do it...

How it works...

Parsing JSON data

Getting ready

How to do it...

How it works...

Social sharing

Getting ready

How to do it...

How it works...

Persisting Data with Core Data

Introduction

Designing data models

How to do it...

How it works...

Reading and inserting records to Core Data

How to do it...

How it works...

Updating and deleting records from Core Data

How to do it...

How it works...

Notifications

Introduction

Setting up Push Notifications

Getting ready

How to do it...

How it works...

Setting up a local server to send Push Notifications

Getting ready

How to do it...

How it works...

Working with interactive Push Notifications

How to do it...

How it works...

Working with local notifications

How to do it...

How it works...

App Search

Introduction

App indexing using NSUserActivity

Getting ready

How to do it...

How it works...

There's more...

App indexing using Core Spotlight APIs

How to do it...

How it works...

Optimizing Performance

Introduction

Memory management with ARC

Getting ready

Retain cycles

Working with closures

How to do it...

How it works...

Measuring performance

How to do it...

How it works...

Measuring energy impact

How to do it...

How it works...

On-demand resources

Getting ready

How to do it...

How it works...

Preface

iOS is evolving every year to provide a better experience for its users. Not only the system, but also the hardware of iPhone and iPad devices, which require a powerful system like the iOS to utilize the features of hardware is evolving. The latest release of iOS now comes with great features to give iOS developers the chance to develop mobile apps with new ideas or enhance the experience of current apps with new features. The book tries to cover the new features of iOS and let iOS developers get their hands dirty by writing sample demos with the features to understand how they work. The book is not meant to be a theory book, which talks about technical things, such as new APIs, or about any specific topic. The book is a cookbook that takes you within minutes to the point and guides you to build a simple demo to understand what is going on using examples, which is the best way to make things stick in your mind.

What this book covers

Chapter 1, Swift Programming Language, is a simple revision of Swift 3 and an explanation of the most important topics in Swift.

Chapter 2, The Essentials, covers the most commonly used UI components, such as UIView, gestures, stack views, and so on.

Chapter 3, Integrating with Messages App, talks about one of the hottest features in iOS--how to integrate with the iOS Messages app to add your own stickers or develop extensions.

Chapter 4, Working with Interface Builder, provides tips and tricks while dealing with interface builders, such as storyboards and XIB files. Get your hands dirty with Autolayout and size classes and know how to work with them.

Chapter 5, Working with UITableView, covers one of the most important components in iOS that all iOS developers should be aware of.

Chapter 6, Animations and Graphics, gives your apps a better look by teaching you how to animate views and draw simple shapes.

Chapter 7, Multimedia, helps you to deal with audio and video in iOS. It provides information about how to use filters thanks to the Core Image framework.

Chapter 8, Concurrency, overcomes the fear of using concurrency in iOS by helping you understand how to use dispatch queues and NSOperationQueues with simple examples.

Chapter 9, Location Services, covers the most commonly used operations in location services, such as getting a user's location, adding pins, navigation, and geofencing.

Chapter 10, Security and Encryption, discusses how to secure your app and protect your user's sensitive information using Touch ID for authentication and saving data in a device's Keychain.

Chapter 11, Networking, covers how to establish networking in an iOS app to retrieve data and parse it.

Chapter 12, Persisting Data with Core Data, takes you through the workings of Core Data to persist data and perform CRUD (creation, reading, updating, and deletion) operations.

Chapter 13, Notifications, helps you overcome the hassle of dealing with push notification and setup and gets you started with configuring your project and server to send and receive notifications.

Chapter 14, App Search, looks at making your app content searchable from Spotlight and Safari suggestions.

Chapter 15, Optimizing Performance, showcases how to measure the performance of your app and how to enhance it.

What you need for this book

Any Mac hardware-running macOS system, such as MacBook Pro, MacBook Air, Mac Mini, iMac, or Mac Pro.

Some chapters require testing on an iOS device with iOS 10.0 or later version.

The software requirements are Xcode 8.1 or later, which requires a Mac running macOS 10.11.5 or later, and iOS Simulator 10.0 or later.

Who this book is for

If you are an iOS developer on a quest to develop your perfect iOS app, then this book is for you. It would also prove to be a valuable resource for those who want to get up and running with iOS development through a clear, practical approach. In order to unleash the full potential of this book, basic Swift programming knowledge is necessary.

Sections

In this book, you will find several headings that appear frequently (Getting ready, How to do it, How it works, There's more, and See also).

To give clear instructions on how to complete a recipe, we use these sections as follows:

Getting ready

This section tells you what to expect in the recipe, and describes how to set up any software or any preliminary settings required for the recipe.

How to do it...

This section contains the steps required to follow the recipe.

How it works...

This section usually consists of a detailed explanation of what happened in the previous section.

There's more...

This section consists of additional information about the recipe in order to make the reader more knowledgeable about the recipe.

See also

This section provides helpful links to other useful information for the recipe.

Conventions

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: The sort function gives us another flexibility by which you can provide a closure that returns the comparison result between any two items in the list to determine which should come first in the list.

A block of code is set as follows:

{ (parameters) ->returnType in

  // block of code goes here

}

Any command-line input or output is written as follows:

cd path_to_directory

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: Under Relationship Segue, click on view controllers to make this view controller part of the view controllers list on the tab bar controller.

Warnings or important notes appear in a box like this.

Tips and tricks appear like this.

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Downloading the example code

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Downloading the color images of this book

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Errata

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Questions

If you have a problem with any aspect of this book, you can contact us at [email protected], and we will do our best to address the problem.

Swift Programming Language

In this chapter, we will cover the following topics:

Using closures to create self-contained code

Creating enumerations to write readable code

Working with protocols and delegates

Using extensions to extend classes functionality

Working with memory management and ARC

Using error handling

Using generics to write generic and reusable code

Introduction

Welcome to our first chapter in iOS Programming Cookbook. We will start our journey in this book with a revision or emphasize on the most important and commonly used topics in Swift programming language. Before talking about these topics, ensure that you have a basic knowledge about Swift programming language and have used it before.

It has been more than 2 years since Apple released the awesome programming language-Swift. Swift is meant to be easy to code, easy to learn, safe, and intuitive. For each version of Swift, Apple introduces some awesome features and enhancements in the language. As we see in Swift 2.0, Swift came with higher performance, and new APIs such as error handling, and some enhancements. Swift is not meant to be available in iOS development only; you may find it in other platforms later in the future, thanks to the announcement of Apple that Swift will become open source.

Our recipes in this chapter will focus on the most important topics in Swift that will be used frequently in iOS development. When you focus on these topics and learn them properly, you will find using them in development will make your life easier and your code will be more organized. There are many people who can write code, but only few can write awesome code. Thus, mastering these topics is very important to be a good developer and to help you and others working on a project.

For the latest features of Swift, ensure that you are using the latest version of Xcode.

Using closures to create self-contained code

Closures are self-contained lines of code to be executed and passed like any other data types. You should be familiar with blocks or at least heard about them in Objective-C or C. This recipe will help you to understand closure syntax and get familiar in using them.

Getting ready

Closures syntax in Swift is pretty easy and is easier than the syntax in C or Objective-C. The general form of closure is as follows:

{ (parameters) ->returnType in

  // block of code goes here

}

As you see, you first put open curly braces, add list of parameters and the return type, then the keyword in, followed by lines of code in your closure. Closures are first-class type, which means it can be nested, passed in parameters, returned from function, and so on.

How to do it...

Go to Xcode and create a new playground file called Closures to test code about closures in it.

To see closures in action, copy and paste this piece of code in the playground file (the output of each statement is printed on the right):

      var names = [David, Jones, Suzan, Naomi, Adam]

      names.sort() // [Adam, David, Jones, Naomi, Suzan]

      names.sort{ (str1: String, str2: String) ->Bool in

        return str1 > str2

      }

      // [Suzan, Naomi, Jones, David, Adam]

How it works...

Swift provides us with a built-in system function called sort. The function can sort any collection of data. The function, by default, will sort the collection in an ascending order. The sort function gives us another flexibility by which you can provide a closure that returns the comparison result between any two items in the list to determine which should come first in the list.

As we saw, the default sort function sorts our data in an ascending order; in order to do any other logic, we can sort with closure that gives you two items as parameters to decide how to compare them. The sort function sorts the collection in place, and that's why the names variable is created as var not let. If the names collection is defined as let, you will not be able to use the sort() function. There is another function called sorted(), which returns a totally new sorted collection without changing the original one. It's available in both versions of the collection with var or let.

There's more...

Even though the closure syntax looks simple, but Swift can make it simpler. Let's see how closure syntax can be optimized.

Inferring type

When closures are passed as argument like what we did in the sort function, Swift can infer the types of closure parameters and return type. In that case, we can omit the parameters and return types, as there is no need to write them. In our previous example, when we infer types, the sort function would be like this:

names.sort{ str1, str2 in

  return str1 > str2

}

As you can see, the String types and the return type have been omitted.

Omitting the return keyword

Swift can make your life easier than that. When closure body consists of only one expression, the return keyword can be omitted. So, the new version of sort function will be like this:

names.sort({ str1, str2 in str1 > str2})

Shorthand arguments

To reach the maximum awesomeness of Swift, you can refer to the argument list with names $0, $1, and so on. When you decide to use the shorthand arguments, you can omit the list of parameters. You may ask what about the in keyword, will it be alone? The answer is no, we won't leave it alone; we can omit it as well completely. Here is the final version of our sort function:

names.sort({ $0 > $1})

Creating enumerations to write readable code

Using enumerations is one of the best practices that you should follow while writing any software project and not only iOS projects. Once you find that you have a group of related values in your project, create enum to group these values and to define a safe type for these values. With enumerations, your code becomes more readable and easy to understand, as it makes you define new types in your project that map to other value. In Swift, enumerations have been taken care of and have become more flexible than the ones used in other programming languages.

Getting ready

Now, we will dive into enumerations and get our hands dirty with it. To do so, we will create a new playground file in Xcode called Enumerations so that we can