Seven Mobile Apps in Seven Weeks

Seven Mobile Apps in Seven

Weeks

Native Apps, Multiple Platforms

by Tony Hillerson

Version: P1.0 (July 2016)

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Table of Contents

Acknowledgments

The Story So Far...

The Only Constant

Who Should Read This Book?

Seven Mobile Apps

The Platforms

System Requirements and Useful Tools

Don’t Get Comfortable

Online Resources

1. Day 0: Setting Up the API

Setting Up and Running the API

Reviewing and Testing the Endpoints

Now We’re Ready

Part I. Official Native Platforms

2. Mobile Web

A World-Clock App

Day 1: A Time for Beginnings

Day 2: Making Time

Day 3: Time to Move

Wrapping Up the Web App

3. iOS

A Weather-Forecast App

Day 1: What’s It Like Out?

Day 2: What’s It Like There?

Day 3: Expanding Our Horizons

Wrapping Up iOS

4. Android

A Currency-Conversion App

Day 1: How Far Does a Dollar Go?

Day 2: What Can I Get for a Buck?

Day 3: Time Is Money

Wrapping Up Android

5. Universal Windows Platform

A Stock-Quote App

Day 1: The Initial Investment

Day 2: Trending Up

Day 3: A Wider Market

Wrapping Up Windows Phone

Part II. Cross-Platform Tools

6. RubyMotion

A To-Do App

Day 1: ✓ Android

Day 2: ✓ iOS

Day 3: ✓ Cross-Platform

Wrapping Up RubyMotion

7. Xamarin

A Calculator App

Day 1: Adding Up the Platforms

Day 2: Dividing Up the Solution

Day 3: Subtracting Platform-Specific Code

Wrapping Up Xamarin

8. React Native

A Note-Taking App

Day 1: Comparing Notes

Day 2: Exchanging Notes

Day 3: Taking Note of Where We Are

Wrapping Up React Native

9. Wrapping Up

Official Native Platforms

Cross-Platform Tools

What’s Next?

Copyright © 2016, The Pragmatic Bookshelf.

Early praise for Seven Mobile Apps in

Seven Weeks

Tony does an excellent job at explaining the Xamarin concepts to first-time

users! His fun tutorials keep the reader engaged while teaching them step-by￾step to create their first mobile app in C#.

→ Brandon Minnick

Customer-success engineer, Xamarin

The mobile software development landscape has never been wider than it is

today. Tony Hillerson’s Seven Mobile Apps in Seven Weeks is a wonderful

approach to showcasing the many options available for mobile application

development. You’ll find this book is a valuable learning asset regardless of

whether you’re starting fresh in the industry or looking to pick up experience on

another mobile platform. This book is the "Three Wolf Moon" of the mobile

software development world.

→ Joshua Jamison

Software engineer, Ride

This book will teach you so much about mobile native and hybrid development

by taking you on an in-depth journey exploring many approaches to create

incredible apps across all the major platforms. An incredible and versatile source

of knowledge that I recommend to any developer of any level.

→ Daniel Wanja

VP of engineering, Blinker

I found this book much more engaging than I had anticipated. I am impressed by

the author’s ability to cover the material with a delicate balance between

glossing over important details and providing too much detail— overwhelming

the reader. I highly recommend this title to anyone interested in a practical head￾to-head comparison of modern mobile application-development approaches.

→ Daniel Lamb

Senior software engineer; Technical architect and author, CoStar Group

Acknowledgments

When people ask where I got the concept for this book, I joke that it sprang fully

formed into my head because I needed to answer questions about or build apps

for multiple mobile platforms so many times. It certainly feels that way, but

what most likely happened was that I had hundreds of conversations with

coworkers, friends, clients, and industry experts about building apps for multiple

platforms. Add to those conversations the great esteem I have for the Seven in

Seven series, and you can see how I came to the conclusion to write this book.

So, then, thank you to all of my coworkers and friends with whom I’ve had these

conversations and built those apps over the years. We commiserated, we argued,

we experimented, we built stuff, and I learned a great deal from all of you.

Thank you also to Dave and Andy, the publishers; Bruce, the Seven in Seven

series editor; and Jackie, the editor of this book, for helping me to make this an

addition to the series that I enjoy so much. I really appreciate the opportunity.

Writing a book like this, with seven technologies, requires more eyes than just

mine on the code; it requires the help of reviewers both reviewing the book as a

whole and diving deeply into technologies as experts. Here are the reviewers

who made this book possible by finding bugs and corrections and offering style

tips and encouragement. Thanks to all of you:

Michael Hunter, Kevin Garriott, Daniel Wanja, Loren Sands-Ramshaw, Maricris

Nonato, Javier Collado, Alessandro Bahgat, Daniel Lamb, Nishant Srivastava,

Gábor László Hajba, Ramaninder Singh Jhajj, Stephen Wolff, Stefan Turalski,

Kaan Karaca, Fabrizio Cucci, Jacob Henry, Colin Gray, Seth Howard, Eric

Langland, Rob Malko, Brandon Minnick, Jack Moffitt, and Joshua Jamison.

Finally, thanks to my wife, Lori, and our kids, Diāna, Lincoln, and Titus, for

allowing me the time to write another book.

Copyright © 2016, The Pragmatic Bookshelf.

The Story So Far...

In the beginning there was a mobile platform, and it was good. It ran on the best

mobile hardware available, both phones and tablets. It had an app store, where

consumers could buy new software for their mobile devices. Developers liked to

develop for this platform because the devices had fancy UIs, powerful SDKs

were available, and people could make money from the app store to support their

development.

There was a competing platform, though, and a lot of those devices looked pretty

good, too. But it wasn’t that easy to develop on. Its marketplace wasn’t as good

and the toolset was really hard to work with. If you were a developer on the first

platform, it didn’t seem very appealing to try to learn a whole different platform.

If you had a good thing going, there was not a lot of value in learning all new

tools instead of spending time building apps you already knew how to build. The

best bet was to stick with what was comfortable and just ride that gravy train to

an early retirement.

And then everything changed.

The Only Constant

In case you didn’t already guess, the mobile platform I was just talking about

was Windows Mobile. Back in the days before the iPhone changed the mobile

space, Windows Mobile had a pretty good thing going. It already had everything

the iPhone introduced: an app store (by a different name) and good tools (for the

time), and it ran on pretty sweet devices (by those days’ standards). It had a big

competitor, or maybe more than one—who can remember back that far? The

point is that if you were making your living by developing Windows Mobile

apps then, there’s a really good chance you no longer are. Not that it would have

helped to have been proficient at more than one platform when iOS came out

and made them all pretty much obsolete. The point is not how many platforms

you’re proficient on, but rather how proficient you are at learning new platforms.

As software developers, we’ve learned that the platforms we build software on

change pretty often. If you pick a durable language to learn really well, chances

are you can get some mileage out of it, but you’re always having to learn new

SDKs, new APIs, new libraries. And of course, even languages can become

obsolete. With apologies to anyone still using it, I no longer include Cold Fusion

on my resumé.

The Seven in Seven series has always been about expanding your horizons, about

becoming a polyglot and a connoisseur of new ideas in software. You don’t learn

new languages or frameworks just because that’s a fun pastime, although it can

be, but because learning a new language, framework, or platform exposes you to

new paradigms and idioms, different ways to solve problems. At some point you

realize that recognizing the similarities and differences between languages or

platforms makes you think about building software at a higher level, no matter

what tool you’re using at the time. At some point in your career you are no

longer an “X developer”—where X is whatever platform you prefer—and instead

you have become a “software developer."

Who Should Read This Book?

To get the most out of this book, you need to buy in to the premise of the Seven

in Seven series. The best way I can express that is that you fully believe that

continually exploring and learning about software development is your

responsibility as a developer. What you get in return is the inspiration, guidance,

and interesting problems that can help you maximize your time spent learning.

That means that this book isn’t a replacement for the official documentation; it

doesn’t spend a lot of time telling you how to get set up, and the platform

coverage isn’t comprehensive. Instead, this book provides you with a very useful

tool: problems to solve in order to help you learn. Each week you’ll build a

nontrivial app over three days, and you’ll also get some ideas of how you can

take the app further yourself.

This book is focused on modern mobile platforms. Those are the “official”

platforms: mobile web, iOS, Android, and Windows. Closely related are three

cross-platform tools: RubyMotion, Xamarin, and React Native. The selling point

of these tools is that, to some greater or lesser extent, building apps for one or

more of the official platforms is easier, and you can share code between the

platforms.

If you’ve never done any mobile development before, it’s best if you have

software-development experience of some kind. This book is most helpful for

answering the following questions about each platform:

How does it feel to develop on this platform?

How does this platform compare to the others?

And, for the cross-platform tools, what are their pros and cons over

developing for one or more of the official platforms?

If you’re a software developer who wants to dive into mobile development, this

book will help you make a solid comparison between the platforms. If you’re

already a mobile developer for one platform, this book will give you a great

framework for evaluating another platform. And if you’ve ever wondered or

framework for evaluating another platform. And if you’ve ever wondered or

been asked by a client or manager if a cross-platform development tool is the

right one for the job, this book will help you answer that question about three

popular choices.

Seven Mobile Apps

Over the course of this book, we’ll build seven mobile apps. The point of

building the apps is to explore the platforms. To that end each of the apps have a

number of design goals.

App-Design Goals

Not every app hits every goal, but each reaches a large enough subset to give

you a really good taste of building for the target platform. Here is a list of design

goals.

The apps should have enough view code that you get a feel for how

interface-building works.

All apps have some level of navigation, multiple screens, or at least

multiple views.

All apps deal with displaying collections of data. This is something that

happens all the time, so we cover it.

The apps all make HTTP requests to a JSON API, so you should have a

great idea of how to request data from the web. In some cases we’ll also

post data.

Most apps include some information on designing and building interfaces

for multiple screen sizes and orientations.

Most apps give you an idea of how to store data locally.

These design goals won’t make you an expert on the platform, but they will give

you an idea of what it’s like to work with common use cases.

How a Week Works

Each platform is designed to be explored over a week. There are chapters for

three days of guided development, and each day ends with some suggested next