This document contains various information regarding usage of libosmscout for/under Android using the Qt backend as part of Qt applications under Android.

Installation of the Android development environment under Arch Linux

Instructions are for compiling under x86_64 Arch Linux.

Activate multilib, see https://wiki.archlinux.org/index.php/multilib and https://wiki.archlinux.org/index.php/Arch64_FAQ

Install the Android AUR packages: https://wiki.archlinux.org/index.php/android

I did not install any platforms at this point, since the android-qt5 package will install relevant AUR packages (platform versions 10, 11, 16) anyway.

Install the normal Qt development environment and also the package android-qt5. Make sure that the Qt versions match. This will also pull in the android-ndk package.

set environment variable ANDROID_NDK_ROOT, the variable should point to the root of the NDK. (in case of arch linux: /opt/android-ndk)

Because we want to use the C++ compiler together with the stl, we need to create a standalone toolchain. For this call using root rights:

make-standalone-toolchain.sh \ –verbose \ –toolchain=arm-linux-androideabi-4.8 \ –system=linux-X86_64 \ –install-dir=/home/tim/projects/arm-linux-androideabi-4.8

The install directory of course could be places somewhere else

set environment variable ANDROID_SYSROOT, the variable should point to the to be used platform tools sysroot directory. (/home/tim/projects/arm-linux-androideabi-4.8/sysroot im my case).

Cross compilation of libosmscout, libosmscout-map and libosmscout-map-qt

The Android SDK/NDK supports various toolschains for various platforms, in the following examples we target arm-linux-androideabi, which is used by most modern Android mobiles. We also target API level 16, which corresponds to Android 4.1.2 - things however should work similar for other platforms and API versions.

extend the path to contain bin directory of your toolchain (/home/tim/projects/arm-linux-androideabi-4.8/bin)

set a number of environment variables to point to the corresponding files in the toolchain directory:

export CPP=arm-linux-androideabi-cpp export CC=arm-linux-androideabi-gcc export CXX=arm-linux-androideabi-g++ export LD=arm-linux-androideabi-ld

export CPPFLAGS="--sysroot=$ANDROID_SYSROOT -march=armv7-a -mfloat-abi=softfp -mfpu=vfp" export CFLAGS="--sysroot=$ANDROID_SYSROOT -march=armv7-a -mfloat-abi=softfp -mfpu=vfp" export CXXFLAGS="--sysroot=$ANDROID_SYSROOT -march=armv7-a -mfloat-abi=softfp -mfpu=vfp"

export PKG_CONFIG_LIBDIR=$ANDROID_SYSROOT/lib

Note that I'm not sure regarding the correct directory for PKG_CONFIG_LIBDIR. However in this example it was just important that it did not find the libraries on the host.

Note that PKG_CONFIG_SYSROOT_DIR should possibly also have been set, but in this case this would force us to install libosmscout for its headers to be found because all paths in the *.pc would be prefixed with the variable content.

Note that PKG_CONFIG_PATH should point to the various used libosmscout-* directories and to the directory of the Android-Qt package containing the *.pc files (under arch linux: /opt/android-qt5/5.3.0/lib/pkgconfig/)

For Android version-less libraries have to get build (requirement of the device local shared library loader). Standard under Linux are versioned libraries. It is the task of the used libtool package to do platform dependend compiler/linker calls, however libtool currently does not have special handling for Android. Android is thus detected as Linux and this versioned libraries are build. You have to patch your local m4/libtool.m4 to get the special handling for Android. Apply the following patch:

http://lists.gnu.org/archive/html/libtool-patches/2013-06/msg00002.html

Note that autoconf may reinstall the official libtool.m4 if autogen.sh is called. You then have to reapply the patch.

Now configure and compile the libraries using: ./configure –host=arm-linux-androideabi –with-sysroot=$ANDROID_SYSROOT –disable-openmp-support

Note that openmp seams to be not supported (I got crashes quickly) so disable it using the above configure option for configure scripts that test for it (libosmscout).

Note that the pkg-config tool used is that from the build system, so availability of libs detected via pkg-config is not based on the host (target) system but on the build system.

Under Android qmake ignores pkg-config calls (it assumes that evaluating pkg-config does not make sense while cross compiling). You have to ensure that pkg-config is used (and the libosmscout libraries found) by adding

QT_CONFIG -= no-pkg-config

to the OSMScout2 project file.

Goto the OSMScout2 directory and call the qmake from the Android-Qt5 package to generate a makefile. (under arch linux: /opt/android-qt5/5.3.0/bin/qmake).

Build OSMScout2 by calling make.

Building the Android *.apk fro the sources

We assume that the package will get build in the "android-pkg" sub directory (of the OSMScout2 directory). Any templates will be searched in the sub directory "android".

We clean up the existing directory:

rm -rf android-pkg

Then we install the OSMScout application into the android-pkg directory:

make install INSTALL_ROOT=android-pkg

We then call the Qt androiddeployqt application:

/opt/android-qt5/5.3.0/bin/androiddeployqt –input android-libOSMScout.so-deployment-settings.json –output android-pkg –android-platform android-16 –verbose –install

In this case we use the *.json file generated by the build as information base, place the package into the "nadroid-pkg" directory, build for platform 16, output a number of details and finally install the package directly onto the device (you must have USB debugging on the mobile active and the mobile connected and detected vi USB).

Since the path to the libosmscout libraries is already (hardcoded) in the project file, these dependend libraries will get automatically placed into the package.

That's it.