added dockerfile for android build

docker/BuildAndroid.dockerfile

@@ -0,0 +1,40 @@
+FROM ubuntu:noble
+WORKDIR /usr/local/app
+
+RUN apt-get update && apt-get install -y openjdk-17-jdk python3 pipx cmake ccache ninja-build wget git xz-utils
+
+ENV PIPX_HOME="/opt/pipx"
+ENV PIPX_BIN_DIR="/usr/local/bin"
+ENV PIPX_MAN_DIR="/usr/local/share/man"
+RUN pipx install 'conan<2.0'
+RUN pipx install 'sdkmanager==0.6.10'
+
+RUN conan profile new conan --detect
+
+RUN wget https://github.com/vcmi/vcmi-dependencies/releases/download/1.3/dependencies-android-arm64-v8a.txz
+RUN tar -xf dependencies-android-arm64-v8a.txz -C ~/.conan
+RUN rm dependencies-android-arm64-v8a.txz
+
+ENV JAVA_HOME="/usr/lib/jvm/java-17-openjdk-amd64"
+ENV ANDROID_HOME="/usr/lib/android-sdk"
+ENV GRADLE_USER_HOME="/vcmi/.cache/grandle"
+ENV GENERATE_ONLY_BUILT_CONFIG=1
+
+RUN sdkmanager --install "platform-tools"
+RUN sdkmanager --install "platforms;android-34"
+RUN yes | sdkmanager --licenses
+
+RUN conan download android-ndk/r25c@:4db1be536558d833e52e862fd84d64d75c2b3656 -r conancenter
+
+CMD ["sh", "-c", " \
+    # switch to mounted dir
+    cd /vcmi ; \
+    # install conan stuff
+    conan install . --install-folder=conan-generated --no-imports --build=never --profile:build=default --profile:host=CI/conan/android-64-ndk ; \
+    # link conan ndk that grandle can find it
+    mkdir -p /usr/lib/android-sdk/ndk ; \
+    ln -s -T ~/.conan/data/android-ndk/r25c/_/_/package/4db1be536558d833e52e862fd84d64d75c2b3656/bin /usr/lib/android-sdk/ndk/25.2.9519653 ; \
+    # build
+    cmake --preset android-daily-release ; \
+    cmake --build --preset android-daily-release \
+"]

docs/developers/Building_Android.md

@@ -68,3 +68,17 @@ cmake --build ../build
 ```
 
 You can also see a more detailed walkthrough on CMake configuration at [How to build VCMI (macOS)](./Building_macOS.md).
+
+## Docker
+
+For developing it's also possible to use docker to build an android APK. As requirement only a installed docker is needed. The container image contains all other prerequisites.
+
+To build using docker just open a terminal with `vcmi` as working directory.
+
+Build the image with (only needed once):
+`docker build -f docker/BuildAndroid.dockerfile -t vcmi-android-build .`
+
+After building the image you can compile vcmi with:
+`docker run -it --rm -v $PWD/:/vcmi vcmi-android-build`
+
+The current dockerfile is ARM64 only but can adjusted manually for ARM32.