Chapter 1

All about Android

IN THIS CHAPTER

Your take on Android (depending on who you are)

A tour of Android technologies

Until the mid-2000s, the word "Android" stood for a mechanical humanlike creature - a rootin' tootin' officer of the law with built-in machine guns, or a hyperlogical space traveler who can do everything except speak using contractions. But in 2005, Google purchased Android, Inc. - a 22-month-old company creating software for mobile phones. That move changed everything.

In 2007, a group of 34 companies formed the Open Handset Alliance. The Alliance's task was (and still is) "to accelerate innovation in mobile and offer consumers a richer, less expensive, and better mobile experience." The Alliance's primary project is Android - an open, free operating system based on the Linux operating system kernel.

HTC released the first commercially available Android phone near the end of 2008, but the public's awareness of Android and its potential didn't surface until early 2010. By the mid-2010s, the world had more than 400 Android device manufacturers with 500 mobile carriers using Android and 1.5 million Android activations each day (https://expandedramblings.com/index.php/android-statistics/). By mid-2019, more than 2.5 billion active devices ran the Android operating system (https://venturebeat.com/2019/05/07/android-passes-2-5-billion-monthly-active-devices/). (We know. By the time you read this book, the year 2019 is old news. That's okay.)

This chapter introduces Android. The chapter examines Android from a few different angles.

The Consumer Perspective

A consumer considers the mobile phone alternatives.

Possibility #1: No mobile phone.

• Advantages: Inexpensive. No junk calls. No interruptions. No GPS tracking or snooping by businesses or other agencies.
• Disadvantages: No instant contact with friends and family. No calls to services in case of an emergency. No hand-held games, no tweeting, tooting, hooting, homing, roaming, or booping. And worst of all, to break up with your boyfriend or girlfriend, you can't simply send a text message.

Possibility #2: A feature phone - a mobile phone that's not a smartphone.

• Advantages: Cheaper than a smartphone.

• Disadvantages: Not as versatile as a smartphone. Not nearly as cool as a smartphone. Nowhere near as much fun as a smartphone.

  There's no official rule defining the boundary between feature phones and smartphones. But generally, a feature phone is one with an inflexible menu of home-screen options. A feature phone's menu items relate mostly to traditional mobile phone functions, such as dialing, texting, and maybe some limited web surfing and gaming. In contrast, a smartphone's home screen provides access to the underlying file system and has icons, customizable skins, and many other features that used to be available only to general-purpose computer operating systems.

  Don't write off feature phones. As late as March 2019, Counterpoint Research predicted that people will buy a billion feature phones between 2019 and 2022 (https://www.counterpointresearch.com/more-than-a-billion-feature-phones-to-be-sold-over-next-three-years/). This fact may shock you if you live in a country where feature phones are passé. But in 2019, the worldwide feature phone continued to grow.

Possibility #3: An iPhone.

• Advantages: Great graphics.
• Disadvantages: Little or no flexibility with the single-vendor iOS operating system. Only a handful of different models to choose from. No sanctioned "rooting," "modding," or "jailbreaking" the phone. And then there is the potential cost of an iPhone when compared to Android phones.

Possibility #4: An Ubuntu Touch phone, a Harmony OS phone, or some other non-Android, non-Apple smartphone.

• Advantages: Having a smartphone without belonging to a crowd.
• Disadvantages: Relatively difficult to get technical support. Not nearly as many apps as Android phones and Apple phones. Smaller selection of hardware to choose from.

Possibility #5: An Android phone.

• Advantages: Using an open platform. Using a popular platform with lots of industry support and with powerful market momentum. Writing your own software and installing the software on your own phone (without having to deal with Apple as an intermediary). Access to a broad range of hardware and price points. Publishing software without facing the challenging approval process used by Apple, plus you can choose not to use the Google Play Store (see https://www.knowband.com/blog/mobile-app/alternatives-for-publishing-android-app-on-google-play-store/ for alternative ideas).
• Disadvantages: Security concerns when using an open platform. Confusion about the variety of manufacturers, each with different hardware and with some changes to the Android platform. Dismay when iPhone users make fun of your phone.

Android's advantages far outweigh the possible disadvantages. And you're reading a paragraph from Android Application Development All-in-One For Dummies, 3rd Edition, so you're likely to agree.

Having decided to go with an Android phone, the consumer asks, "Which phone?" And the salesperson says, "This phone comes with Android 10." (If you read between the lines, what the salesperson really means is "This phone comes with Android 9, which will eventually be upgraded to Android 10, or so claims the vendor.") So the consumer asks, "What are the differences among all the Android versions?"

The Versions of Android

Android comes with a few different notions of "version." Android has platform numbers, API levels, codenames, and probably some other versioning schemes. (The acronym API stands for Application Programming Interface - a library full of prewritten programs available for use by a bunch of programmers. In this case, the "bunch" consists of all Android developers.)

To complicate matters, the versioning schemes don't increase in lockstep. For example, Android 8 (codenamed Oreo) has two API levels - levels 26 and 27. But Android 9 (codenamed Pie) has only one API level - level 28.

An Android version may have variations. For example, you can develop for plain old API Level 29 with an established set of features. To plain old API Level 29, you can add the Google APIs (thus adding Google Maps functionality) and still be using platform API Level 29. You can also add a special set with features tailored for a particular device manufacturer or a particular mobile service provider.

API levels 3 through 28 had tasty dessert codenames, and the names came in alphabetical order. For example, after Lollipop came Marshmallow; after Marshmallow came Nougat. Sad to say, the last-ever Android dessert codename was Pie, released in August 2018. About a year later, Google released a newer version simply named Android 10. The number 10 doesn't taste good the way lollipops and pies do.

Figure 1-1 has a summary of Android's API versions from 2008 to 2019.

A few notes on Figure 1-1 are in order:

• The platform number is of interest to the consumer and to the company that sells the hardware. If you're buying a phone with Android 9.0, for example, you might want to know whether the vendor will upgrade your phone to Android 10.0.
• The API level (also known as the SDK version) is of interest to the Android app developer. For example, in API level 8.1, the word Build.SERIAL stands for the phone's serial number. So, you might be tempted to type Build.SERIAL in code that uses API level 9.0. But in API level 9.0, Build.SERIAL doesn't help you get a phone's serial number. In API level 9.0, the value of Build.SERIAL is "UNKNOWN".
• The codename is of interest to the creators of Android. A codename (also known as the version code) refers to the work done by the creators of Android to bring Android to the next level. Picture Google's engineers working for months behind closed doors on Project Oreo, and you'll be on the right track.

Since 2016, a new version of Android has come roughly once a year. Google released Nougat in 2016, Oreo in 2017, Pie in 2018, and the sugarless Android 10 in 2019. As a developer, your job is to balance portability with feature richness. When you create an app, you specify a minimum Android version. (You can read more about specifying a minimum version in Chapter 4 of this minibook.) The higher the version, the more features your app can have. But the higher the version, the fewer the devices that can run your app.

FIGURE 1-1: Android version history.

This book contains tips and tricks for striking a happy medium between whiz-bang features and universal use, and Google has some nifty tools to help you sort out the differences among Android versions. In Chapter 3 of...