2. Setting Up for Development

Android developers write and test applications on their computers and then deploy those applications onto the actual device hardware for further testing.

In this chapter, you’ll become familiar with all the tools you need to master in order to develop Android applications. You’ll learn information about configuring your development environment both on a virtual device and on real hardware. You’ll also explore the Android SDK and all it has to offer.

To develop Android applications, you need to have the following software installed on your computer:

The Java Development Kit (JDK), Version 7, available for download at http://oracle.com/technetwork/java/javase/downloads/index.html (or http://java.sun.com/javase/downloads/index.jsp, if you’re nostalgic). If you are developing on Mac OS X, you should use the Java Runtime Environment (JRE), Version 6, to run Android Studio, and then configure your projects to run JDK 7.

The latest Android SDK. In this book, we will cover using the Android SDK included with Android Studio, which is available for Windows, Mac, or Linux and can be downloaded at http://d.android.com/sdk/index.html. Android Studio includes everything you will need for working on the examples in this book and for developing Android applications. Other items included with Android Studio are the SDK Tools, Platform Tools, the latest Android platform, and the latest Android System image for the emulator.

A compatible Java IDE is required. Luckily, Android Studio is provided, and is based on the free Community Edition of IntelliJ IDEA, and IDE for Java Development. Android Studio comes with the most recent Android SDK already installed. This book focuses on using Android Studio. An alternative to using Android Studio would be to use IntelliJ IDEA Community or Ultimate Edition, or your own copy of Eclipse, but unfortunately, the Eclipse Android Developer Tools plugin is no longer supported so we can only recommend that you use Android Studio for this reason.

An up-to-date and complete list of Android development system requirements is available at http://d.android.com/sdk/index.html.

The basic installation process follows these steps:

1. Download and install the appropriate JRE/JDK for your operating system.

2. Download and install or unzip the appropriate Android Studio package for your operating system. When installing Android Studio, make sure to select all the available components for your system setup, as seen on the Choose Components dialog of the Android Studio Setup wizard seen in Figure 2.1. The last component, Performance (Intel® HAXM) may not be available on your device for installation, but don’t worry if that particular component is not available. Make sure the Android SDK and the Android Virtual Device are selected for installation.

3. Launch Android Studio and use the Android SDK Manager to download and install specific Android platform versions and other components you might use, including the documentation, USB drivers, and additional tools. The Android SDK Manager has been integrated directly into Android Studio and is also available as a stand-alone tool accessible from within Android Studio. In terms of which components you’ll want to choose for installing, we recommend a full installation (choose everything).

4. Configure your computer for device debugging by installing the appropriate USB drivers, if necessary.

5. Configure your Android device(s) for device debugging.

6. Start developing Android applications.

In this book, we do not give you detailed, step-by-step instructions for installing each and every component listed in the preceding steps for these main reasons:

This is an intermediate/advanced book, and we expect you to have some familiarity with installing Java development tools and SDKs.

The Android Developer website provides fairly extensive information about installing development tools and configuring them on a variety of different operating systems. Instructions for installing Android Studio are available at http://d.android.com/sdk/installing/index.html?pkg=studio and instructions for installing the stand-alone SDK are available at http://d.android.com/sdk/installing/index.html?pkg=tools.

The exact steps required to install the Android SDK tend to change subtly with each release, so you’re always better off checking the Android Developer website for the latest information.

Keep in mind that the Android SDK, Android Studio, and tools are updated frequently and may not exactly match the development environment used in this book, as defined in the Introduction, and may look different on your machine than what has been presented in this book. That said, we will help you work through some of the later steps in the process described in this section, starting after you’ve installed and configured the JDK and Android Studio in step 2 of the basic installation process listed above. We’ll poke around in the Android SDK and look at some of the core tools you’ll need to use to develop applications. Then, in the next chapter, you’ll test your development environment and write your first Android application.

Devices that have Android 4.2+ require enabling Developer Options for testing your applications on real hardware. We will be discussing how to configure your hardware for working with Android 4.2+, but if you are working with a different version of Android, check out the following link to learn how to get set up with your version: http://d.android.com/tools/device.html#setting-up. Different versions of Android use different setup methods, so just perform the method for the version you have.

You’ll need to enable your device to install Android applications other than those from the Google Play store. This setting is reached by navigating to Settings, then choosing Security. Here, you should check (enable) the option called Unknown sources, as shown in Figure 2.3. If you do not enable this option, you cannot install developer-created applications, the sample applications, or applications published on alternative markets without the developer tools. Loading applications from servers or even email is a great way to test deployments.

Several other important development settings are available on the Android device by selecting Settings, and then Developer options (see Figure 2.4).

Here, you should enable the USB debugging option. This setting enables you to debug your applications via the USB connection.

The Beta Channel is reserved for installing features that are near the stable, beta features of Android Studio. The Dev Channel is for installing features that were once bleeding edge features that have survived the cut. The Canary Channel is for installing the most recent bleeding edge features. With that said, expect to run into many bugs and issues if you decide to use the Canary Channel.

Changes to the Android SDK might include addition, update, and removal of features; package name changes; and updated tools. With each new version of the SDK, Google provides the following useful documents:

An Overview of Changes: A brief description of the major changes to the SDK

An API Diff Report: A complete list of specific changes to the SDK

Release Notes: A list of known issues with the SDK

These documents are available with every new release of the Android SDK. For instance, Android 5.1 information is available at http://d.android.com/about/versions/android-5.1.html, and Android 5.0 information is available at http://d.android.com/about/versions/android-5.0.html.

You can find out more about adding and updating SDK packages at http://d.android.com/sdk/installing/adding-packages.html.

The Issue Tracker website for the Android open-source project is https://code.google.com/p/android/issues/list. For more information about logging your own bugs or defects for consideration by the Android platform development team, check out the following website: http://source.android.com/source/report-bugs.html.

However, IntelliJ IDEA Ultimate Edition may be worth considering if the project you are working on involves other aspects such as Web development or backend server development using languages like Python, Ruby, PHP, HTML, CSS, or JavaScript, or if you use Web frameworks such as Spring, GWT, Node.js, Django, Rails, or others. Having a single IDE may be beneficial, rather than having to manage a single project across many different IDEs. If you find your project and job duties extend beyond just Android development, take a look at IntelliJ IDEA Ultimate.

IntelliJ IDEA Community Edition is free to download and use, but the Ultimate Edition requires purchasing a commercial or personal license. JetBrains does offer special pricing to qualifying startups, and offers Ultimate for free to qualifying students and teachers, open-source projects, and for education and training purposes. To learn more about IntelliJ IDEA or pricing information, please see https://www.jetbrains.com/idea. For a full list of the differences between the Community and Ultimate Edition of IntelliJ, see https://www.jetbrains.com/idea/features/editions_comparison_matrix.html.

Even if someone at your company has agreed to the licensing agreement on your behalf, it is important for you, the developer, to be aware of a few important points:

Rights granted: Google (as the copyright holder of Android) grants you a limited, worldwide, royalty-free, nonassignable, and nonexclusive license to use the SDK solely to develop applications for the Android platform. Google (and third-party contributors) are granting you the license, but they still hold all copyrights and intellectual property rights to the material. Using the Android SDK does not grant you permission to use any Google brands, logos, or trade names. You may not remove any of the copyright notices therein. Third-party applications that your applications interact with (other Android apps) are subject to separate terms and fall outside this agreement.

SDK usage: You may only develop Android applications. You may not make derivative works from the SDK or distribute the SDK on any device, or distribute part of the SDK with other software.

SDK changes and backward compatibility: Google may change the Android SDK at any time, without notice and without regard to backward compatibility. Although Android API changes were a major issue with prerelease versions of the SDK, recent releases have been reasonably stable. That said, each SDK update does tend to affect a small number of existing applications in the field, thus necessitating updates.

Android application developer rights: You retain all rights to any Android software you develop with the SDK, including intellectual property rights. You also retain all responsibility for your own work.

Android application privacy requirements: You agree that your application will protect the privacy and legal rights of its users. If your application uses or accesses personal and private information about the user (usernames, passwords, and so on), your application must provide an adequate privacy notice and keep that data stored securely. Note that privacy laws and regulations may vary by user location; you as a developer are solely responsible for managing this data appropriately.

Android application malware requirements: You are responsible for all applications you develop. You agree not to write disruptive applications or malware. You are solely responsible for all data transmitted through your application.

Additional terms for specific Google APIs: Use of the Google Maps Android API is subject to further Terms of Service. You must agree to these additional terms before using those specific APIs and always include the Google Maps copyright notice provided. Use of Google APIs (Google apps such as Gmail, Blogger, Google Calendar, YouTube, and so on) is limited to accessing what the user has explicitly granted permission for during installation time.

Develop at your own risk: Any harm, financial or otherwise, that comes about from developing with the Android SDK is your own fault and not Google’s.

Several optional third-party APIs are available outside the core Android SDK. These packages must be installed separately from their respective websites or from within the Android SDK Manager when available. Some packages are from Google, whereas others are from device manufacturers and other providers. Some of the most popular third-party APIs are described in Table 2.2.

For a complete list of Google Play services APIs, see https://developers.google.com/android/guides/setup. For a complete list of all Google products that may have Android APIs, see https://developers.google.com/products/.

Android Studio incorporates many of the most important Android SDK tools seamlessly and provides various wizards for creating, debugging, and deploying Android applications. The Android SDK tools add useful functions to Android Studio. Buttons are available on the toolbar, including those that perform the following Android actions (see Figure 2.6):

Launch the Android Virtual Device Manager

Launch the Android SDK Manager

Launch the Android Device Monitor

These tools perform two major functions: management of the developer’s AVD configurations and management of Android SDK components installed on the development machine.

Much like desktop computers, different Android devices run different versions of the Android operating system. Developers need to be able to target different Android SDK versions with their applications. Some applications target a specific Android SDK, whereas others try to provide simultaneous support for as many versions as possible.

The Android Virtual Device Manager organizes and provides tools to create and edit AVDs. To manage applications in the Android emulator, you must configure different AVD profiles. Each AVD profile describes what type of device you want the emulator to simulate, including which Android platform to support as well as what the device specifications should be. You can specify different screen sizes and orientations, and you can specify whether the emulator has an SD card and, if so, what its capacity is, among many other device configuration settings.

The Android SDK Manager facilitates Android development across multiple platform versions simultaneously. When a new Android SDK is released, you can use this tool to download and update your tools while still maintaining backward compatibility and use older versions of the Android SDK.

The emulator is a generic device and is not tied to any one specific phone configuration. You describe the hardware and software configuration details that the emulator is to simulate by providing an AVD configuration. Figure 2.10 shows what the emulator might look like with a typical Android 5.1 smartphone-style AVD configuration.

Figure 2.11 shows what the emulator might look like with a typical Android 5.1 tablet-style AVD configuration. Both Figures 2.10 and 2.11 show how the Settings application behaves differently on different devices.

Many sample applications are available to demonstrate different aspects of the Android SDK. Some focus on generic application development tasks while others focus on demonstrating specific APIs.

As of API 23, some of the sample code that you should look into further is categorized as follows:

Getting started: includes samples demonstrating common Android components such as the action bar, floating action button, and more

Background: includes samples demonstrating common tasks that should be run in the background

Input: includes samples demonstrating common input methods such as gestures, multitouch, and swipes

Media: includes samples demonstrating media-related features such as the camera, recording, effects, and others

Connectivity: includes samples demonstrating various networking methods such as Bluetooth and HTTP

Notification: includes samples demonstrating various Notification APIs

Wearable: includes many samples demonstrating the various features available to developers for wearable devices

The examples above are just a few of the many categories of applications that are available as samples that demonstrate various features of the Android APIs.

2. What security option must be selected on an Android hardware device for installing your own applications without using an Android marketplace?

3. What option must be enabled on your hardware device to debug your applications?

4. What is the name of the .jar file that comprises the Android application framework?

5. What is the top-level package name for unit-testing support?

6. Which optional Android SDK is provided by Google for integrating advertising in your applications?

2. Launch the Android Studio SDK Manager of Android Studio and install at least one other version of Android.

3. Name five sample applications provided with the Android SDK.

http://d.android.com/guide/components/index.html

Android SDK download site:

http://d.android.com/sdk/index.html

Android SDK License Agreement:

http://d.android.com/sdk/terms.html

The Java Platform, Standard Edition:

http://oracle.com/technetwork/java/javase/overview/index.html

JetBrains:

https://www.jetbrains.com/

Android Developer Tools:

https://developer.android.com/tools/help/adt.html

The Eclipse Project:

http://eclipse.org