In Debian stretch, the upcoming new release, it is now possible to build Android apps using only packages from Debian. This will provide all of the tools needed to build an Android app targeting the "platform" android-23 using the SDK build-tools 24.0.0. Those two are the only versions of "platform" and "build-tools" currently in Debian, but it is possible to use the Google binaries by installing them into /usr/lib/android-sdk.

This doesn't cover yet all of the libraries that are used in the app, like the Android Support libraries, or all of the other myriad libraries that are usually fetched from jCenter or Maven Central. One big question for us is whether and how libraries should be included in Debian. All the Java libraries in Debian can be used in an Android app, but including something like Android Support in Debian would be strange since they are only useful in an Android app, never for a Debian app.

Building apps with these packages

Here are the steps for building Android apps using Debian's Android SDK on Stretch.

1. sudo apt install android-sdk android-sdk-platform-23
2. export ANDROID_HOME=/usr/lib/android-sdk
3. In build.gradle, set compileSdkVersion to 23 and buildToolsVersion to 24.0.0
4. run gradle build

The Gradle Android Plugin is also packaged. Using the Debian package instead of the one from online Maven repositories requires a little configuration before running gradle. In the buildscript block:

• add maven { url 'file:///usr/share/maven-repo' } to repositories
• use compile 'com.android.tools.build:gradle:debian' to load the plugin

Currently there is only the target platform of API Level 23 packaged, so only apps targeted at android-23 can be built with only Debian packages. There are plans to add more API platform packages via backports. Only build-tools 24.0.0 is available, so in order to use the SDK, build scripts need to be modified. Beware that the Lint in this version of Gradle Android Plugin is still problematic, so running the :lint tasks might not work. They can be turned off with lintOptions.abortOnError in build.gradle. Google binaries can be combined with the Debian packages, for example to use a different version of the platform or build-tools.

Why include the Android SDK in Debian?

While Android developers could develop and ship apps right now using these Debian packages, this is not very flexible since only build-tools-24.0.0 and android-23 platform are available. Currently, the Debian Android Tools Team is not aiming to cover the most common use cases. Those are pretty well covered by Google's binaries (except for the proprietary license on the Google binaries), and are probably the most work for the Android Tools Team to cover. The current focus is on use cases that are poorly covered by the Google binaries, for example, like where only specific parts of the whole SDK are used. Here are some examples:

• tools for security researchers, forensics, reverse engineering, etc. which can then be included in live CDs and distros like Kali Linux
• a hardened APK signing server using apksigner that uses a standard, audited, public configuration of all reproducibly built packages
• Replicant is a 100% free software Android distribution, so of course they want to have a 100% free software SDK
• high security apps need a build environment that matches their level of security, the Debian Android Tools packages are reproducibly built only from publicly available sources
• support architectures besides i386 and amd64, for example, the Linaro LAVA setup for testing ARM devices of all kinds uses the adb packages on ARM servers to make their whole testing setup all ARM architecture
• dead simple install with strong trust path with mirrors all over the world

In the long run, the Android Tools Team aims to cover more use cases well, and also building the Android NDK. This all will happen more quickly if there are more contributors on the Android Tools team! Android is the most popular mobile OS, and can be 100% free software like Debian. Debian and its derivatives are one of the most popular platforms for Android development. This is an important combination that should grow only more integrated.

Last but not least, the Android Tools Team wants feedback on how this should all work, for example, ideas for how to nicely integrate Debian's Java libraries into the Android gradle workflow. And ideally, the Android Support libraries would also be reproducibly built and packaged somewhere that enforces only free software. Come find us on IRC and/or email! https://wiki.debian.org/AndroidTools#Communication_Channels