lqml/readme-prepare-android.md

Install android development tools

A good description of what you'll need can be found here:

doc.qt.io/qt-5/android-getting-started

You don't need Android Studio, so search for command line tools on the SDK download page.

The NDK version to use depends on the Qt version. Qt5.15 requires 21.3, Qt6 requires 25c.

The latest working SDK for Qt5.15 is e.g. /opt/android/sdk/platforms/android-34. If you find versions greater than 34 in your SDK platforms path, you need to move them to another directory before compiling APKs.

Define environment variables and aliases

Put this in e.g. ~/.bashrc:

  export JAVA_HOME='<path-to-jdk>'
  export ANDROID_HOME='<path-to-sdk>'
  export ANDROID_NDK_ROOT='<path-to-ndk>'
  export ANDROID_NDK_TOOLCHAIN='<path-to-ndk>/toolchains/llvm/prebuilt/linux-x86_64'
  export ECL_ANDROID='<path-to-cross-compiled-ecl>/ecl-android'

  # optional
  export ECL_ANDROID_32='<path-to-cross-compiled-ecl-32>/ecl-android'

  alias qmake-android='<path-to-qt5.15>/android/bin/qmake'

Add the path of the platform tools (.../sdk/platforms-tools) to your path, so we can use adb:

  export PATH=$PATH:/<path-to-platform-tools>

(Use source ~/.basrhc to make new environment variables take effect immediately in your current terminal session.)

Build cross-compiled ECL for android

To build the cross-compiled ECL aarch64, just use the 2 scripts included in this project. You'll need latest ECL 23.9.9.

• extract a fresh copy of the ECL sources in e.g. ~/ecl, and rename ecl-23.9.9 to android
• copy the 2 scripts from platforms/android/build-ecl/ to ~/ecl/android/
• run both scripts in order

  ./1-make-ecl-host.sh
  ./2-make-ecl-android.sh

Now you should have your cross-compiled ECL under ~/ecl/android/ecl-android/,
and your host ECL (for cross-compiling) under ~/ecl/android/ecl-android-host/.

Build 32bit ECL (optional)

For older devices you may need a 32bit version. Just use the build scripts in platforms/android/build-ecl/32bit/ and set ECL_ANDROID_32 (see above).

Before running the scripts, you need to add this on top of file src/bdwgc/pthread_stop_world.c:

#undef USE_TKILL_ON_ANDROID

For 32bit builds you need to substitute every qmake-android ... with:

qmake-android "CONFIG+=32bit" ...

Just use the respective build-android/ directory for building, and remember to do a make clean before running make.