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Android applications, like most mobile phone applications, are
developed in a host-target development environment. In other words, you
develop your application on a host computer (where resources are abundant)
and download it to a target mobile phone for testing and ultimate use.
Applications can be tested and debugged either on a real Android device or
on an emulator. For most developers, using an emulator is easier for
initial development and debugging, followed by final testing on real
devices. To write your own Android mobile phone applications, you’ll first
need to collect the required tools and set up an appropriate development
environment on your PC or Mac. The Android SDK supports several different integrated development environments (IDEs). No matter which operating system you
are using, you will need essentially the same set of tools: The Eclipse IDE Sun’s Java Development Kit (JDK) The Android Software Developer’s Kit (SDK) The Android Developer Tool (ADT), a special Eclipse
plug-in
Since you’re probably going to develop on only one of the host
operating systems, skip to the appropriate section that pertains to your
selected operating system. 1. Creating an Android Development EnvironmentThe Android Software Development Kit supports Windows (XP and Vista), Linux (tested on Ubuntu Dapper Drake, but any recent Linux distro should
work), and Mac OS X (10.4.8 or later, Intel platform only) as host
development environments. Installation of the SDK is substantially the
same for any of the operating systems, and most of this description
applies equally to all of them. Where the procedure differs, we will
clearly tell you what to do for each environment: Install JDK: The Android SDK requires JDK version 5 or version 6. If
you already have one of those installed, skip to the next step. In
particular, Mac OS X comes with the JDK version 5 already installed,
and many Linux distributions include a JDK. If the JDK is not
installed, go to http://java.sun.com/javase/downloads and you’ll see a
list of Java products to download. You want JDK 6 Update
n for your operating system, where
n is 6 at the time of this writing.
Windows (XP and Vista) Select the distribution for “Windows Offline
Installation, Multi-language.” Read, review, and accept Sun’s license for the JDK.
(The license has become very permissive, but if you have a
problem with it, alternative free JDKs exist.) Once the download is complete, a dialog box will ask
you whether you want to run the downloaded executable.
When you select “Run,” the Windows Installer will start up
and lead you through a dialog to install the JDK on your
PC.
Linux Select the distribution for “Linux self-extracting
file.” Read, review, and accept Sun’s license for the JDK.
(The license has become very permissive, but if you have a
problem with it, alternative free JDKs exist.) You will need to download the self-extracting binary
to the location in which you want to install the JDK on
your filesystem. If that is a system-wide directory (such
as /usr/local), you
will need root access. After the file is downloaded, make it
executable (chmod +x
jdk-6version-linux-i586.bin),
and execute it. It will self-extract to create a tree of
directories.
Mac OS X Mac OS X comes with JDK version 5 already loaded.
Install Eclipse:
The Android SDK requires Eclipse version 3.3 or later. If
you do not have that version of Eclipse installed yet, you will need
to go to http://www.eclipse.org/downloads to
get it, and you might as well get version 3.4 (also known
as Ganymede), since that package includes the required
plug-ins mentioned in the next step. You want the version of the
Eclipse IDE labeled “Eclipse IDE for Java Developers,” and obviously
you want the version for your operating system. Eclipse will ask you
to select a mirror site, and will then start the download.
Windows (XP or Vista) The Eclipse download comes as a big ZIP file that you
install by extracting the files to your favorite directory. Eclipse is now
installed, but it will not show up in your Start menu of
applications. You may want to create a Windows shortcut for
C:/eclipse/eclipse.exe
and place it on your desktop, in your Start menu, or someplace
else where you can easily find it.
Linux and Mac OS X Note that, as of this writing, the version of Eclipse
installed if you request it on Ubuntu Hardy Heron is 3.2.2,
which does not contain all the plug-ins needed for Android. The Eclipse
download comes as a big tarball (.gz
file) that you install by extracting the files to your
favorite directory.The executable
itself is located in that directory and is named eclipse.
Check for required plug-ins:
You can skip this step if you just downloaded a current
version of Eclipse as we recommended. If you are using a
preinstalled version of Eclipse, you need to make sure you have
the Java Development Tool (JDT) and Web Standard Tools
(WST) plug-ins. You can easily check to see whether they are
installed by starting Eclipse and selecting menu options “Windows →
Preferences...”. The list of
preferences should include one for “Java” and one for either “XML”
or “Web and XML.” If they aren’t on the list, the easiest thing to
do is reinstall Eclipse, as described in the previous step.
Installing “Eclipse IDE for Java Developers” will automatically get
the needed plug-ins. Install Android SDK:
This is where you should start if you already have the
right versions of Eclipse and the JDK loaded. The Android SDK is
distributed through Google’s Android site, http://developer.android.com/sdk/1.1_r1/index.html.
You will need to read, review, and accept the terms of the license
to proceed. When you get to the list of downloads, you will see a
table of distributions. Select the one for your operating system (XP
and Vista use the same distribution). The package (file) names
include the release number. For example, as this is written, the
latest version of the SDK is
1.1_r1, so the filename for Windows is android-sdk-windows-1.1_r1.zip. For versions 3.3 and later of Eclipse, the Android download
site provides directions about how to install the plug-in through
Eclipse’s software updates utility. If you’re using Eclipse 3.2 or
the software update technique doesn’t work for you, download the SDK
from the Android site and install it using instructions in the next
paragraph. The file you download is another archive file, as with
Eclipse: a ZIP file on Windows, a tar-zipped file for Linux and
MacOS X. Do the same thing as for Eclipse: extract the archive file
to a directory where you want to install Android, and make a note of
the directory name (you’ll need it in step 6). The extraction will
create a directory tree containing a bunch of subdirectories,
including one called tools. Update the environment
variables: To make it easier to launch the Android tools, add the
tools directory to your
path. On Windows XP, click on Start, then right-click on My Computer. In the
pop-up menu, click on Properties. In the resulting System
Properties dialog box, select the Advanced tab. Near the bottom
of the Advanced tab is a button, “Environment Variables,” that
takes you to an Environment Variables dialog. User environment
variables are listed in the top half of the box, and System
environment variables in the bottom half. Scroll down the list
of System environment variables until you find “Path”; select
it, and click the “Edit” button. Now you will be in an Edit
System Variable dialog that allows you to change the environment
variable “Path.” Add the full path of the tools directory to the end of the
existing Path variable and click “OK.” You should now see the
new version of the variable in the displayed list. Click “OK”
and then “OK” again to exit the dialog boxes. On Windows Vista, click on the Microsoft “flag” in the
lower left of the desktop, then right-click on Computer. At the
top of the resulting display, just below the menu bar, click on
“System Properties.” In the column on the left of the resulting
box, click on “Advanced system settings.” Vista will warn you
with a dialog box that says “Windows needs your permission to
continue”; click “Continue.” Near the bottom of the System
Properties box is a button labeled “Environment Variables” that
takes you to an Environment Variables dialog. User environment
variables are listed in the top half of the box, and System
environment variables in the bottom half. Scroll down the list
of System environment variables until you find “Path”; select
it, and click the “Edit” button. Now you will be in an Edit
System Variable dialog that allows you to change the environment
variable “Path.” Add the full path of the tools directory to the end of the
existing Path variable, and click “OK.” You should now see the
new version of the variable in the displayed list. Click “OK”
and then “OK” again to exit the dialog boxes. On Linux, the PATH environment variable can be defined in
your ~/.bashrc
~/.bash_profile file. If you have either of those files, use a text editor
such as gedit,
vi, or Emacs to open the file and look for
a line that exports the PATH variable. If you find such a line,
edit it to add the full path of the tools directory to the path. If there
is no such line, you can add a line like this: export PATH=${PATH}:your_sdk_dir/toolswhere you put the full path in place of
your_sdk_dir. On Mac OS X, look for a file named .bash_profile in your home directory
(note the initial dot in the filename). If there is one, use an
editor to open the file and look for a line that exports the
PATH variable. If you find such a line, edit it to add the full
path of the tools directory
to the path. If there is no such line, you can add a line like
this: export PATH=${PATH}:your_sdk_dir/toolswhere you put the full path in place of
your_sdk_dir.
Install the Android plug-in
(ADT): We will make use of the Android
Development Tool plug-in that Google supplies for use in building
Android applications. The plug-in is installed in much the same way
as any other Eclipse plug-in: Start Eclipse, if it’s not already running. From the menu bar, select “Help → Software Updates → Find
and Install...”. In the Install/Update dialog, select “Search for new
features to install” and click on “Next.” In the Install dialog, click on “New Remote Site.” A “New
Update Site” dialog pops up. Enter a name for the plug-in
(“Android Plugin” will do), and the URL for updates: https://dl-ssl.google.com/android/eclipse. Click
“OK.” The new site should now appear in the list of sites on the
Install dialog. Click “Finish.” In the Search Results dialog, select the checkbox for
“Android Plugin → Developer Tools” and click
“Next.” The license agreement for the plug-in appears. Read it,
and if you agree, select “Accept terms of the license agreement”
and click “Next.” Click “Finish.” You will get a warning that the plug-in is not signed.
Choose to install it anyway by clicking “Install All.” After Eclipse restarts, you need to tell it where the SDK
is located. From the menu bar, select “Window → Preferences.” In
the Preferences dialog, select “Android” in the left
column. Use the “Browse” button to navigate to the place you
installed the Android SDK, and click on “Apply,” then on
“OK.”
Congratulations—you have installed a complete Android development
environment without spending a penny. The environment includes a very sophisticated set
of tools to make Android programming easier, including: An Integrated Development Environment based on Eclipse, arguably the premier IDE for Java
development. Eclipse itself brings many valuable development
features. Google and OHA have taken advantage of Eclipse’s
extensibility to provide features customized for Android, including
debugging capabilities that are tuned to the needs of mobile
application developers like you. A Java development environment and Dalvik virtual machine that build on Sun’s JDK
foundation to provide a very sophisticated programming environment
for your applications. A complete mobile phone emulator that allows you to test your
applications without having to download them to a target mobile
phone. The emulator includes features for testing your application under
different mobile phone communication conditions (fading, dropped
connections, etc.). Test tools, such as Traceview, which allow you to tune your
application to take best advantage of the limited resources
available on a mobile phone.
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