Using Docker for KDE on Android Development

This is the easiest way to start cross-compiling and developing Qt applications for Android. The explained Docker image will install all dependencies and setup all environment variables automatically. By this, it closely follows the steps explained in the detailed system setup guide:

Setup Cross-Building Environment for KDE on Android

Setting up

This image alone contains a working Android SDK, NDK and Qt binaries. The easiest is to access it like this (it will be downloaded the first time you use it):

docker run -ti --rm kdeorg/android-sdk bash

Here one can start developing at ease in an environment welcoming to projects that use cmake, Qt, ECM, etc.

Building a KDE application

To make it easy to compile applications we put some scripts to get started. They can be triggered like this:

docker run -ti --rm kdeorg/android-sdk /opt/helpers/build-generic <appname>

Using Volumes

Since we are giving --rm to docker run everything will be lost once we exit the bash shell from the Setting up section or when the build-generic command from the Building an application ends.

This is particularly bad for the Building an application case since it will compile your application, create the .apk and then immediately it will get lost :)

To solve that we can use volumes. Volumes are a way for docker to punch out of themselves into your local filesystem.

For example if we want to save the output of the build-generic command (that ends up in /output inside the docker container) we can do

docker run -ti --rm -v $HOME/apks:/output kdeorg/android-sdk /opt/helpers/build-generic okular

the extra -v $HOME/apks:/output means: whatever would be written to /output inside the docker container write it to $HOME/apks in my actual filesystem (if you're curious this is achieved via bind mounts)

You can pass multiple -v arguments. For example:

if you already have the source code downloaded in your local filesystem you can pass -v $HOME/path/to/kde/sources:/home/user/src (/home/user is the docker home path)
if you want to keep the build artifacts to not have to compile everything all the time you can pass -v $HOME/place/to/store/android/build/artifacts:/home/user/build.

Advanced Usage

The enviroment comes with several helper scripts to make it easier to build stuff for Android!

To run the scripts you need to be in a shell inside the container.

Build a framework

/opt/helpers/build-kde-project ki18n Frameworks

Replace ki18n by the name of the framework you want to build

Build a custom application

If you want to create an APK later you need to get some cmake args first

python /opt/helpers/get-apk-args.py src/yourapp/

Now we can build the app. Replace <ARGS> by the output of the previous command. foo technically is supposed to be the git url for your app, but that doesn't matter if it's already checked out.

/opt/helpers/build-cmake yourapp foo <ARGS>"

There are also scripts for other build systems like /opt/helpers/build-autotools. Here you can find all available scripts

Create an APK

If you have build your app like described in the previous section you can now create an APK with

/opt/helpers/create-apk yourapp