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Android 1: Background

Kirk Scott

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• 1.1 Buzzwords• 1.2 Development Software• 1.3 Getting Started• 1.4 Preliminaries to Trying to Make It Work

the First Time

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1.1 Buzzwords

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• Android started as a separate company• It was acquired by Google• It is supported by the Open Handset Alliance

(OHA)• Android involves many cooperating companies• Together they’re providing a non-proprietary

software development environment

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Key components of this successful alliance are:

• Hardware device manufacturers• Mobile service providers• Android/Google, which provides the basic

software operating and development environments

• Independent app developers marketing through the app store or other places

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The platform is based on:

• A secure operating system, Linux• Virtual machines running on top of Linux

(known as Dalvik virtual machines)• A widely-known object-oriented language,

Java• A tested software development environment,

Eclipse

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Proprietary vs. non-proprietary

• Android is based on open source licensing• Developers do not have to pay fees to use the

development tool kit• The do not have to pay fees on the apps

developed with it

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• A term for software development infrastructure is “Application Programming Interface

• This is known as the API• In Android, the API for independent

developers includes everything that a “native” (Google) programmer would have access to

• There are no secrets

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• The theory is that there is a large potential market

• By opening up the environment, you increase the size of the pie for everyone

• Android is growing from phones to tablets to other devices

• The growth is being driven by the app market

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Another useful aspect of the development environment:

• It comes with an emulator for handheld devices

• This means that you can initially develop and test code on a PC with the development environment installed

• You don’t literally have to develop on the handheld device

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Emulation isn’t Perfect

• The emulator is slow• The emulator can be problematic• The emulator may not fully model the

hardware device of interest• The reality is that you eventually have to test

and finish development on a hardware device if you expect to roll out the app on that device

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Versions

• You may have heard of “Ice Cream Sandwich” (ICS), Jellybean, or KitKat

• These are some of the recent versions of the Android SDK (software development kit)

• The different versions have been named after sweets in alphabetical order

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1.2 Development Software

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• To start developing for Android you essentially need to download and install two pieces of software:

• The Java SDK (software development kit)• The Android Development Toolkit (ADT)

bundle

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• The bundle includes Android classes for development

• It includes the emulator so that you can start to learn development without access to an Android hardware device

• It includes Eclipse with several important features for Android development

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• These overheads do not explain the complete process of downloading and installing

• Some information is given in case you want to try to install on your own system

• Expect problems and expect to have to search for solutions online

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Downloads

• The first step is installing Java on your system• The entry point for downloading Java is

www.oracle.com• On that Web page there is a link for downloads• Under that heading you can find Java for

developers• Find the right Java SDK for your system and

install it before installing the Android tools

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• The highest level entry point for Android is www.android.com

• On this Web page you’ll find a link for developers or you can go directly to developer.android.com

• Find the ADT bundle which is right for your system and install it

• For the time being, just accept the defaults, whatever they might be

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The Android Web Site

• Virtually anything you might want to know about Android programming can be found at the developer’s Web site

• The site includes tutorials on app development

• It includes Java-style documentation of the packages and classes in the Android API

• It includes detailed technical information

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Overhead Contents

• The problem is:• There is too much information• You don’t know where to start• You can’t tell what’s important• It’s overwhelming• These overheads are supposed to provide a

guide to getting started

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• Keep these things in mind:• 1. There are lots of things that you simply

don’t have to be told about at the beginning• They may be covered in the future if they’re

needed

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• 2. There are lots of things where you will have to accept that they exist

• You will have to learn how to use them at a minimal level without having any idea of how they work

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• At the beginning you will be doing a lot of work just to get the Android machinery to run a very simple app

• For the time being you will have to accept the machinery without explanation

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1.3 Getting Started

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• The starting point for the following overheads is a successful installation of Java and the ADT bundle on your system

• Once the ADT is installed, your entry point into Android development will be Eclipse

• In addition to the standard Java programming features, Eclipse in the ADT bundle includes features for Android programming

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The Eclipse Interface

• A screenshot of the Eclipse interface is shown on the following overhead

• It is open to a Java source file for an Android app

• The tools come up tiny, but you may be able to sort them out

• These tools are also available through the menu if the toolbar isn’t showing

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• Another screenshot of the Eclipse interface is shown on the following overhead

• This is a preview of coming attractions• It shows an Android layout for the app code

shown in the previous screen shot• This will be explained in greater detail later

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What is included with Eclipse as part of the ADT bundle:

• There is an Android SDK Manager tool• There is an Android Virtual Device Manager

tool• And there is a DDMS (Dalvik Debug Monitor

Server) perspective• Many items appear in the tool bar• There is also an extensive set of menu choices

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• The Android SDK Manager tool allows you to keep the SDK installation up to date

• In the toolbar the icon is the top half of the Android with a down arrow in place of the bottom half

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• The Android Virtual Device Manager tool allows you to set up virtual devices to test your software on

• In the toolbar it’s located next to the Android SDK Manager tool

• The icon is essentially the one shown below, but on the screen it’s so microscopic that you might not recognize it

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The Android SDK Manager

• A screenshot of the Android SDK Manager tool is shown on the following overhead

• As noted, the tool allows you to manage and update what is installed on your development machine

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The Android Virtual Device Manager

• A screenshot of the Android Virtual Device Manager tool is shown on the overhead following the next one

• At the moment the details are unimportant• We will be using the tool soon enough• It is presented now because it emphasizes the

idea that you can develop on an emulator

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• The “virtual device” manager is that part of the environment which makes it possible to define and manage emulators

• Emulation isn’t perfect, but it’s a helpful• Even though you may only own one physical

handheld device, you can try out an application on different devices with emulation

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1.4 Preliminaries to Trying to Make It Work the First Time

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Preliminary Remarks

• Trying to make things work the first time is not always easy

• No set of instructions or screen shots can preview exactly what you will have to do

• It is not possible to anticipate all of the problems that might occur along the way

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• Hardware can be different• Software installations can be different• Every programmer/user’s level of

technological mastery can be different

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Emulator Problems

• One big problem in practice is the emulator• Starting the emulator is painfully slow even on

an up-to-date, reasonably powerful machine with a reasonable amount of memory

• If you try to launch an app on an emulator that hasn’t yet fully started, the app won’t run

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Workspaces

• As you may know from doing Java programming in Eclipse, Eclipse organizes projects and packages in workspaces

• This also holds true when doing Android programming with Eclipse

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The Android Demos/Tutorials in Eclipse

• Depending on your Android installation, when you start up Eclipse the first screen that will be shown is an entry point into the demos/tutorials

• This is shown on the following overhead

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• The first step, “Build Your First App” is the stage we’re at

• This is where to go if you start getting bogged down in these overheads and you want an alternative presentation

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Summary and Mission

• There is no assignment and no hands-on exercises for this unit

• Eclipse from the ADT has both Java development features and features especially for Android development

• A little information was given as a starting point for installing the ADT on a machine of your own

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The End