Revision as of 13:18, 9 September 2020

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 an 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 achived 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.

@@ Line 1: / Line 1: @@
-= Use Docker Container for KDE on Android Development =
+= 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:
 * [[Android/Environment|Setup Cross-Building Environment for KDE on Android]]
-== Use Docker Container ==
+== Setting up ==
-First, you must install Docker on your system, which should be available via your distribution. Then you only have to checkout the Docker image configuration in <code>git clone git://anongit.kde.org/android-builder.git</code>.
+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):
+<syntaxhighlight lang="bash">
+docker run -ti --rm kdeorg/android-sdk bash
+</syntaxhighlight>
+Here one can start developing at ease in an environment welcoming to projects that use cmake, Qt, ECM, etc.
-Then in folder <code>image</code> perform the following commands to build, then create, and finally to run your KDE on Android build image:
+== Building an application ==
+To make it easy to compile applications we put some scripts to get started. They can be triggered like this:
 <syntaxhighlight lang="bash">
-cd image
+docker run -ti --rm kdeorg/android-sdk /opt/helpers/build-generic <appname>
-docker build -t kde-android-sdk .
-docker create -ti --name myproject kde-android-sdk bash
-docker start -i myproject
 </syntaxhighlight>
-More details can be found in the README.md file in the checked out repository.
-==== Change Container Size ====
+== Using Volumes ==
-By default Docker containers have a size of 10GB. This is sufficient for the typical use case, but usually much too small if you setup a full cross-building toolchain. For this, you have to increase the default container size (note: the following deletes all your current containers, hence do backups and do it with care!)
+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.
-* Documentation: https://docs.docker.com/engine/reference/commandline/daemon/
+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
 <syntaxhighlight lang="bash">
-service docker stop
+docker run -ti --rm -v $HOME/apks:/output kdeorg/android-sdk /opt/helpers/build-generic okular
-rm -rf /var/lib/docker
-service docker start
-docker -d --storage-opt dm.basesize=20G &
 </syntaxhighlight>
+the extra <code>-v $HOME/apks:/output</code> 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 achived 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 <code>-v $HOME/path/to/kde/sources:/home/user/src</code> ('''/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 <code>-v $HOME/place/to/store/android/build/artifacts:/home/user/build</code>.