Before you distribute your Android application to users you need to prepare it for release. The preparation process is a required development task for all Android applications and is the first step in the publishing process (see figure 1).
When you prepare your application for release, you configure, build, and test a release version of your application. The configuration tasks are straightforward, involving basic code cleanup and code modification tasks that help optimize your application. The build process is similar to the debug build process and can be done using JDK and Android SDK tools. The testing tasks serve as a final check, ensuring that your application performs as expected under real-world conditions. When you are finished preparing your application for release you have a signed APK file, which you can distribute directly to users or distribute through an application marketplace such as Google Play.
This document summarizes the main tasks you need to perform to prepare your application for release. The tasks that are described in this document apply to all Android applications regardless how they are released or distributed to users. If you are releasing your application through Google Play, you should also read Publishing Checklist for Google Play to be sure your release-ready application satisfies all Google Play requirements.
Note: As a best practice, your application should meet all of your release criteria for functionality, performance, and stability before you perform the tasks outlined in this document.
To release your application to users you need to create a release-ready package that users can install and run on their Android-powered devices. The release-ready package contains the same components as the debug APK file — compiled source code, resources, manifest file, and so on — and it is built using the same build tools. However, unlike the debug APK file, the release-ready APK file is signed with your own certificate and it is optimized with the zipalign tool.
Figure 2. You perform five main tasks to prepare your application for release.
The signing and optimization tasks are usually seamless if you are building your application with Android Studio. For example, you can use Android Studio with the Gradle build files to compile, sign, and optimize your application all at once. You can also configure the Gradle build files to do the same when you build from the command line. For more details about using the Gradle build files, see the Build System guide.
To prepare your application for release you typically perform five main tasks (see figure 2). Each main task may include one or more smaller tasks depending on how you are releasing your application. For example, if you are releasing your application through Google Play you may want to add special filtering rules to your manifest while you are configuring your application for release. Similarly, to meet Google Play publishing guidelines you may have to prepare screenshots and create promotional text while you are gathering materials for release.
You usually perform the tasks listed in figure 2 after you have throroughly debugged and tested your application. The Android SDK contains several tools to help you test and debug your Android applications. For more information, see the Debugging and Testing sections in the Dev Guide.
To begin preparing your application for release you need to gather several supporting items. At a minimum this includes cryptographic keys for signing your application and an application icon. You might also want to include an end-user license agreement.
The Android system requires that each installed application be digitally signed with a certificate that is owned by the application's developer (that is, a certificate for which the developer holds the private key). The Android system uses the certificate as a means of identifying the author of an application and establishing trust relationships between applications. The certificate that you use for signing does not need to be signed by a certificate authority; the Android system allows you to sign your applications with a self-signed certificate. To learn about certificate requirements, see Signing Your Applications.
Important: Your application must be signed with a cryptographic key whose validity period ends after 22 October 2033.
You may also have to obtain other release keys if your application accesses a service or uses a third-party library that requires you to use a key that is based on your private key.
Be sure you have an application icon and that it meets the recommended icon guidelines. Your application's icon helps users identify your application on a device's Home screen and in the Launcher window. It also appears in Manage Applications, My Downloads, and elsewhere. In addition, publishing services such as Google Play display your icon to users.
Note: If you are releasing your application on Google Play, you need to create a high resolution version of your icon. See Graphic Assets for your Application for more information.
Consider preparing an End User License Agreement (EULA) for your application. A EULA can help protect your person, organization, and intellectual property, and we recommend that you provide one with your application.
You might also have to prepare promotional and marketing materials to publicize your application. For example, if you are releasing your application on Google Play you will need to prepare some promotional text and you will need to create screenshots of your application. For more information, see Graphic Assets for your Application
After you gather all of your supporting materials you can start configuring your application for release. This section provides a summary of the configuration changes we recommend that you make to your source code, resource files, and application manifest prior to releasing your application. Although most of the configuration changes listed in this section are optional, they are considered good coding practices and we encourage you to implement them. In some cases, you may have already made these configuration changes as part of your development process.
Make sure you choose a package name that is suitable over the life of your application. You cannot change the package name after you distribute your application to users. You can set the package name in application's manifest file. For more information, see the package attribute documentation.
Make sure you deactivate logging and disable the debugging option before you build your
application for release. You can deactivate logging by removing calls to
Log methods in your source files. You can disable debugging by removing the
android:debuggable attribute from the
<application> tag in your
manifest file, or by setting the
android:debuggable attribute to
false in your manifest file. Also, remove any log files or static test files that
were created in your project.
Important: Ensure that you disable debugging for
your app if using
interfaces, since debugging allows users to inject scripts and extract content using Chrome
DevTools. To disable debugging, use the
Clean up your project and make sure it conforms to the directory structure described in Android Projects. Leaving stray or orphaned files in your project can prevent your application from compiling and cause your application to behave unpredictably. At a minimum you should do the following cleanup tasks:
jni/directory should contain only source files associated with the Android NDK, such as
lib/directory should contain only third-party library files or private library files, including prebuilt shared and static libraries (for example,
src/directory should contain only the source files for your application (
src/directory should not contain any
res/directory for old drawable files, layout files, and values files that you are no longer using and delete them.
lib/directory for test libraries and remove them if they are no longer being used by your application.
assets/directory and your
res/raw/directory for raw asset files and static files that you need to update or remove prior to release.
Verify that the following manifest and build files items are set correctly:
You should specify only those permissions that are relevant and required for your application.
You must specify values for these attributes, which are located in the <application> element.
There are several additional manifest or build file elements that you can set if you are releasing your
application on Google Play. For example, the
android:targetSdkVersion attributes, which are located in the <uses-sdk> element. For more
information about these and other Google Play settings, see Filters on Google Play.
Android provides several tools and techniques to make your application compatible with a wide range of devices. To make your application available to the largest number of users, consider doing the following:
Make sure you meet the best practices for supporting multiple screens. By supporting multiple screen configurations you can create an application that functions properly and looks good on any of the screen sizes supported by Android.
If your application is designed for devices older than Android 3.0, make it compatible with Android 3.0 devices by following the guidelines and best practices described in Optimizing Apps for Android 3.0 .
If your application is designed for devices running Android 3.x, make your application compatible with older versions of Android by adding the Support Library to your application project. The Support Library provides static support libraries that you can add to your Android application, which enables you to use APIs that are either not available on older platform versions or use utility APIs that are not part of the framework APIs.
If your application accesses remote servers or services, make sure you are using the production URL or path for the server or service and not a test URL or path.
If you are releasing a paid application through Google Play, consider adding support for Google Play Licensing. Licensing lets you control access to your application based on whether the current user has purchased it. Using Google Play Licensing is optional even if you are releasing your app through Google Play.
For more information about Google Play Licensing Service and how to use it in your application, see Application Licensing.
After you finish configuring your application you can build it into a release-ready APK file that is signed and optimized. The JDK includes the tools for signing the APK file (Keytool and Jarsigner); the Android SDK includes the tools for compiling and optimizing the APK file. If you are using Android Studio or you are using the Gradle build system from the command line, you can automate the entire build process. For more information about configuring Gradle builds, see Configuring Gradle Builds.
You can use the Gradle build system, integrated with Android Studio to build a release-ready APK file that is signed with your private key and optimized. To learn how to setup and run builds from Android Studio, see Building and Running from Android Studio.
The build process assumes that you have a certificate and private key suitable for signing your application. If you do not have a suitable certificate and private key, Android Studio can help you generate one. For more information about the signing process, see Signing Your Applications.
If your application relies on a remote server, make sure the server is secure and that it is configured for production use. This is particularly important if you are implementing in-app billing in your application and you are performing the signature verification step on a remote server.
Also, if your application fetches content from a remote server or a real-time service (such as a content feed), be sure the content you are providing is up to date and production-ready.
Testing the release version of your application helps ensure that your application runs properly under realistic device and network conditions. Ideally, you should test your application on at least one handset-sized device and one tablet-sized device to verify that your user interface elements are sized correctly and that your application's performance and battery efficiency are acceptable.
As a starting point for testing, see What to Test. This article provides a summary of common Android situations that you should consider when you are testing. When you are done testing and you are satisfied that the release version of your application behaves correctly, you can release your application to users. For more information, see Releasing Your Application to Users. If you are publishing your application on Google Play, see Launch Checklist for Google Play.