Compiling for Android

Note

In most cases, using the built-in deployer and export templates is good enough. Compiling the Android APK manually is mostly useful for custom builds or custom packages for the deployer.

Also, you still need to follow the steps mentioned in the Exporting for Android tutorial before attempting to build a custom export template.

Requirements

For compiling under Windows, Linux or macOS, the following is required:

  • Python 2.7+ or Python 3.5+
  • SCons build system
  • Android SDK (command-line tools are sufficient)
    • Required SDK components will be automatically installed by Gradle (except the NDK)
  • Android NDK r17 or later
  • Gradle (will be downloaded and installed automatically if missing)
  • JDK 8 (either OpenJDK or Oracle JDK)
    • JDK 9 or later are not currently supported
    • You can download a build from ojdkbuild

See also

For a general overview of SCons usage for Godot, see Introduction to the buildsystem.

Setting up the buildsystem

Set the environment variable ANDROID_HOME to point to the Android SDK. If you downloaded the Android command-line tools, this would be the folder where you extracted the contents of the ZIP archive. Later on, gradlew will install necessary SDK components in this folder. However, you need to accept the SDK component licenses before they can be downloaded by Gradle. This can be done by running the following command from the root of the SDK directory, then answering all the prompts with y:

tools/bin/sdkmanager --licenses

Set the environment variable ANDROID_NDK_ROOT to point to the Android NDK.

To set those environment variables on Windows, press Windows + R, type “control system”, then click on Advanced system settings in the left pane, then click on Environment variables on the window that appears.

To set those environment variables on Linux or macOS, use export ANDROID_HOME=/path/to/android-sdk and export ANDROID_NDK_ROOT=/path/to/android-ndk where /path/to/android-sdk and /path/to/android-ndk point to the root of the SDK and NDK directories.

Building the export templates

Godot needs two export templates for Android: the optimized “release” template (android_release.apk) and the debug template (android_debug.apk). As Google will require all APKs to include ARMv8 (64-bit) libraries starting from August 2019, the commands below will build an APK containing both ARMv7 and ARMv8 libraries.

Compiling the standard export templates is done by calling SCons with the following arguments:

  • Release template (used when exporting with Debugging Enabled unchecked)
scons platform=android target=release android_arch=armv7
scons platform=android target=release android_arch=arm64v8
cd platform/android/java
# On Windows
.\gradlew build
# On Linux and macOS
./gradlew build

The resulting APK will be located at bin/android_release.apk.

  • Debug template (used when exporting with Debugging Enabled checked)
scons platform=android target=release_debug android_arch=armv7
scons platform=android target=release_debug android_arch=arm64v8
cd platform/android/java
# On Windows
.\gradlew build
# On Linux and macOS
./gradlew build

The resulting APK will be located at bin/android_debug.apk.

Adding support for x86 devices

If you also want to include support for x86 devices, run the SCons command a third time with the android_arch=x86 argument before building the APK with Gradle. For example, for the release template:

scons platform=android target=release android_arch=armv7
scons platform=android target=release android_arch=arm64v8
scons platform=android target=release android_arch=x86
cd platform/android/java
# On Windows
.\gradlew build
# On Linux and macOS
./gradlew build

This will create a fat binary that works on all platforms. The final APK size of exported projects will depend on the platforms you choose to support when exporting; in other words, unused platforms will be removed from the APK.

Using the export templates

Godot needs release and debug APKs that were compiled against the same version/commit as the editor. If you are using official binaries for the editor, make sure to install the matching export templates, or build your own from the same version.

When exporting your game, Godot opens the APK, changes a few things inside and adds your files.

Installing the templates

The newly-compiled templates (android_debug.apk and android_release.apk) must be copied to Godot’s templates folder with their respective names. The templates folder can be located in:

  • Windows: %APPDATA%\Godot\templates\<version>\
  • Linux: $HOME/.local/share/godot/templates/<version>/
  • macOS: $HOME/Library/Application Support/Godot/templates/<version>/

<version> is of the form major.minor[.patch].status using values from version.py in your Godot source repository (e.g. 3.0.5.stable or 3.1.dev). You also need to write this same version string to a version.txt file located next to your export templates.

However, if you are writing your custom modules or custom C++ code, you might instead want to configure your APKs as custom export templates here:

../../_images/andtemplates.png

You don’t even need to copy them, you can just reference the resulting file in the bin\ directory of your Godot source folder, so that the next time you build you will automatically have the custom templates referenced.

Troubleshooting

Application not installed

Android might complain the application is not correctly installed. If so:

  • Check that the debug keystore is properly generated.
  • Check that the jarsigner executable is from JDK 8.

If it still fails, open a command line and run logcat:

adb logcat

Then check the output while the application is installed; the error message should be presented there. Seek assistance if you can’t figure it out.

Application exits immediately

If the application runs but exits immediately, this might be due to one of the following reasons:

  • Make sure to use export templates that match your editor version; if you use a new Godot version, you have to update the templates too.
  • libgodot_android.so is not in libs/<android_arch>/ where <android_arch> is the device’s architecture.
  • The device’s architecture does not match the exported one(s). Make sure your templates were built for that device’s architecture, and that the export settings included support for that architecture.

In any case, adb logcat should also show the cause of the error.