Go support for Android

David Crawshaw

June 2014

Abstract

We propose to introduce Go support for the Android platform. The focus will be on supporting games written in Go. The APIs will be those defined in the Android NDK.

Background

Android is an operating system designed for running apps. An app relies on far more platform libraries and services than are provided by a traditional Unix operating system, which means a direct port of the Go runtime to Android without new APIs would not be particularly useful.

Providing a Go equivalent to the Android platform is intractable. The platform is written in Java and has a huge API surface. Any attempt to wrap these APIs in Go would give an undesirable result: manually built wrappers would lag in features, automatically generated wrappers would lead to ugly Go. And either way, it would be slow.

There is however, a subset of Android apps written against a much smaller C-based API surface provided in the Android NDK: Games. It is feasible to build Go support for Android providing the equivalent features found in the NDK.

Proposal

During the Go 1.4 cycle, GOOS=android will be introduced to the Go repository, along with cgo support on Android (contributed by Elias Naur). Dalvik-loadable .so files will be produced using the external linker provided in the Android NDK.

For the build dashboard, we will maintain a cross-compiling builder that runs the Go tool on a linux host and uses the adb tool to run test binaries on a stock Android device.

We will introduce a subrepository, go.mobile. It will house:

• Bindings for OpenGL, OpenSL, and OpenMAX as exported through the Android NDK.

• A Java -> Go language binding generator. Given a Go package, this will let Java code call it, so game menu UIs can be built in the standard SDK. (As Go defines the binding, it also makes it possible to use the same code to bind to languages like Objective C.)

• Android Studio build system integration.

Binary releases will be provided after the project has stabilized.

Go support for Android