There are two ways to build your application using the Ant build script: one for testing/debugging your application — debug mode — and one for building your final package for release — release mode. Regardless of which way you build your application, it must be signed before it can install on an emulator or device—with a debug key when building in debug mode and with your own private key when building in release mode.
Whether you're building in debug mode or release mode, you need to use the Ant tool to compile and build your project. This will create the .apk file that you can install on an emulator or device. When you build in debug mode, the .apk file is automatically signed by the SDK tools with a debug key, so it's instantly ready for installation onto an emulator or attached development device. You cannot distribute an application that is signed with a debug key. When you build in release mode, the .apk file is unsigned, so you must manually sign it with your own private key, using Keytool and Jarsigner.
It's important that you read and understand Signing Your Applications, particularly once you're ready to release your application and share it with end-users. That document describes the procedure for generating a private key and then using it to sign your .apk file. If you're just getting started, however, you can quickly run your applications on an emulator or your own development device by building in debug mode.
If you don't have Ant, you can obtain it from the Apache Ant home page. Install it and make sure it is in your executable PATH. Before calling Ant, you need to declare the JAVA_HOME environment variable to specify the path to where the JDK is installed.
Note: When installing JDK on Windows, the default is to install
in the "Program Files" directory. This location will cause ant
to fail, because of
the space. To fix the problem, you can specify the JAVA_HOME variable like this:
set JAVA_HOME=c:\Progra~1\Java\<jdkdir>
The easiest solution, however, is to install JDK in a non-space directory, for example:
c:\java\jdk1.6.0_02
Building in Debug Mode
For immediate application testing and debugging, you can build your application in debug mode
and immediately install it on an emulator. In debug mode, the build tools automatically sign your
application with a debug key and optimize the package with zipalign
.
To build in debug mode:
- Open a command-line and navigate to the root of your project directory.
- Use Ant to compile your project in debug mode:
ant debug
This creates your debug
.apk
file inside the projectbin/
directory, named<your_project_name>-debug.apk
. The file is already signed with the debug key and has been aligned withzipalign
.
Each time you change a source file or resource, you must run Ant again in order to package up the latest version of the application.
To install and run your application on an emulator, see the following section about Running on the Emulator.
Building in Release Mode
When you're ready to release and distribute your application to end-users, you must build your application in release mode. Once you have built in release mode, it's a good idea to perform additional testing and debugging with the final .apk.
Before you start building your application in release mode, be aware that you must sign the
resulting application package with your private key, and should then align it using the zipalign
tool. There are two approaches to building in release mode: build an unsigned package
in release mode and then manually sign and align the package, or allow the build script to sign
and align the package for you.
Build unsigned
If you build your application unsigned, then you will need to manually sign and align the package.
To build an unsigned .apk in release mode:
- Open a command-line and navigate to the root of your project directory.
- Use Ant to compile your project in release mode:
ant release
This creates your Android application .apk file inside the project bin/
directory, named <your_project_name>-unsigned.apk
.
Note: The .apk file is unsigned at this point and can't be installed until signed with your private key.
Once you have created the unsigned .apk, your next step is to sign the .apk with your private
key and then align it with zipalign
. To complete this procedure, read Signing Your Applications.
When your .apk
has been signed and aligned, it's ready to be distributed to end-users.
You should test the final build on different devices or AVDs to ensure that it
runs properly on different platforms.
Build signed and aligned
If you would like, you can configure the Android build script to automatically sign and align
your application package. To do so, you must provide the path to your keystore and the name of
your key alias in your project's ant.properties
file. With this information provided,
the build script will prompt you for your keystore and alias password when you build in release
mode and produce your final application package, which will be ready for distribution.
Caution: Due to the way Ant handles input, the password that you enter during the build process will be visible. If you are concerned about your keystore and alias password being visible on screen, then you may prefer to perform the application signing manually, via Jarsigner (or a similar tool). To instead perform the signing procedure manually, build unsigned and then continue with Signing Your Applications.
To specify your keystore and alias, open the project ant.properties
file (found in
the root of the project directory) and add entries for key.store
and key.alias
.
For example:
key.store=path/to/my.keystore key.alias=mykeystore
Save your changes. Now you can build a signed .apk in release mode:
- Open a command-line and navigate to the root of your project directory.
- Use Ant to compile your project in release mode:
ant release
- When prompted, enter you keystore and alias passwords.
Caution: As described above, your password will be visible on the screen.
This creates your Android application .apk file inside the project bin/
directory, named <your_project_name>-release.apk
. This .apk file has
been signed with the private key specified in ant.properties
and aligned with zipalign
. It's ready for installation and distribution.
Once built and signed in release mode
Once you have signed your application with a private key, you can install and run it on an emulator or device. You can also try installing it onto a device from a web server. Simply upload the signed .apk to a web site, then load the .apk URL in your Android web browser to download the application and begin installation. (On your device, be sure you have enabled Settings > Applications > Unknown sources.)
Running on the Emulator
Before you can run your application on the Android Emulator, you must create an AVD.
To run your application:
-
Open the AVD Manager and launch a virtual device
From your SDK's
platform-tools/
directory, execute theandroid
tool with theavd
options:android avd
In the Virtual Devices view, select an AVD and click Start.
-
Install your application
From your SDK's
tools/
directory, install the.apk
on the emulator:adb install <path_to_your_bin>.apk
Your .apk file (signed with either a release or debug key) is in your project
bin/
directory after you build your application.If there is more than one emulator running, you must specify the emulator upon which to install the application, by its serial number, with the
-s
option. For example:adb -s emulator-5554 install path/to/your/app.apk
To see a list of available device serial numbers, execute
adb devices
.
If you don't see your application on the emulator, try closing the emulator and launching the virtual device again from the AVD Manager. Sometimes when you install an application for the first time, it won't show up in the application launcher or be accessible by other applications. This is because the package manager usually examines manifests completely only on emulator startup.
Be certain to create multiple AVDs upon which to test your application. You should have one AVD for each platform and screen type with which your application is compatible. For instance, if your application compiles against the Android 4.0 (API Level 14) platform, you should create an AVD for each platform equal to and greater than 4.0 and an AVD for each screen type you support, then test your application on each one.
Tip: If you have only one emulator running, you can
build your application and install it on the emulator in one simple step. Navigate to the root of
your project directory and use Ant to compile the project with install mode: ant
install
. This will build your application, sign it with the debug key, and install it on
the currently running emulator.
Running on a Device
Before you can run your application on a device, you must perform some basic setup for your device:
- Enable USB debugging on your device.
- On most devices running Android 3.2 or older, you can find the option under Settings > Applications > Development.
- On Android 4.0 and newer, it's in Settings > Developer options.
Note: On Android 4.2 and newer, Developer options is hidden by default. To make it available, go to Settings > About phone and tap Build number seven times. Return to the previous screen to find Developer options.
- Ensure that your development computer can detect your device when connected via USB
Read Setting up a Device for Development for more information.
Once your device is set up and connected via USB, navigate to your SDK's platform-tools/
directory and install the .apk
on the device:
adb -d install path/to/your/app.apk
The -d
flag specifies that you want to use the attached device (in case you also have
an emulator running).
For more information on the tools used above, please see the following documents:
Application Signing
As you begin developing Android applications, understand that all Android applications must be digitally signed before the system will install them on an emulator or device. There are two ways to do this: with a debug key (for immediate testing on an emulator or development device) or with a private key (for application distribution).
The Android build tools help you get started by automatically signing your .apk files with a debug key at build time. This means that you can compile your application and install it on the emulator without having to generate your own private key. However, please note that if you intend to publish your application, you must sign the application with your own private key, rather than the debug key generated by the SDK tools.
The ADT plugin helps you get started quickly by signing your .apk files with a debug key, prior to installing them on an emulator or development device. This means that you can quickly run your application from Eclipse without having to generate your own private key. No specific action on your part is needed, provided ADT has access to Keytool. However, please note that if you intend to publish your application, you must sign the application with your own private key, rather than the debug key generated by the SDK tools.
Please read Signing Your Applications, which provides a thorough guide to application signing on Android and what it means to you as an Android application developer. The document also includes a guide to exporting and signing your application with the ADT's Export Wizard.
Ant Command Reference
ant clean
all
target before clean
(ant all clean
), other projects are also cleaned. For instance if you clean a
test project, the tested project is also cleaned.ant debug
ant emma debug
ant release
ant instrument
emma
target)ant <build_target> install
install
by itself fails.ant installd
.apk
is not
already built.ant installr
.apk
is not
already built.ant installt
.apk
of the
tested application. This fails if the .apk
is not already built.ant installi
.apk
is not already
built.ant test
.apk
files must be
previously installed.ant debug installt test
.apk
files, and
runs the tests.ant emma debug install test
.apk
files, and
runs the tests with code coverage enabled.