View source for Android/Environment

= Setup Environment for KDE on Android Development =
In the following, we explain how to setup a build environment on a Linux system to be able to compile Qt and in particular KF5-based application for Android.

== Prerequisites / Setup of Cross-Compiling Build System ==
At first we prepare your system with all necessary packages to build your application for Android.
For this tutorial we assume that everything is done in the folder '''/opt/android/''' (you can adapt the tutorial accordingly when using another folder).

# Some 32 bit system libraries are required for the host system (because some tools are 32 bit): 
#* libgcc, zlib, libc
#** installing on Debian based system:
#** <code>dpkg --add-architecture i386</code>
#** <code>apt-get install zlib1g:i386 libgcc1:i386 libc6:i386</code>
# Extra-CMake-Modules
#* we require at least version >= 5.15 due to https://git.reviewboard.kde.org/r/125183
#* you can also use a smaller version >= 1.7.0 if applying this change directly to your cmake files
# Android SDK
#* Download: http://developer.android.com/sdk/index.html to /opt/android/ 
#* Unpack, run "tools/android update sdk" and select the following packages:
#** Android SDK Tools (24.3.4)
#** Android SDK Platform-tools (23.0.1)
#** Android SDK Build-tools (22.0.1)
#** Android 5.1.1 (API 22): SDK Platform (only "SDK Platform" needed, i.e. no docs, samples or sources)
#** sys-img-armeabi-v7a-android-22 (required for emulator and unit tests)
#* result: now the SDK should be installed in /opt/android/android-sdk-linux
# Android NDK
#* Download: https://developer.android.com/ndk/index.html to /opt/android/ 
#* unpack the package (see the instructions on the download page)
#* result: now the NDK should be installed in /opt/android/android-ndk-r10e
# Qt with support for Android devices
#* Download the Qt 5.5.0 for Android: https://www.qt.io/download-open-source/#section-2  (32-bit or 64-bit as it fits your host system; usually 64-bit)
#* Variant 1: Offline Installers ("Skip" can be used without problem when asked to register an account)
#* Variant 2: Online installer ("Skip" can be used without problem when asked to register an account)
#* install the following components to /opt/android/Qt5.5.0:
#** Android armv7
#** Qt Creator 3.4.2 (cannot be disabled, some of its tools are used from other parts)
#** Recommended components:
#*** Qt Quick Controls
#*** Qt Location
#*** Qt Script
#*** Optional components (there might be KDE software using it):
#*** Qt WebEngine
#*** Qt Canvas 3D
#*** Qt3D
#*** Qt Quick 1
# Install the following software packages on your host system from your package manager (if not yet installed):
#* CMake: >= 2.8.6
#* Java Development Kit 7 (openjdk-7-jdk) 
#* Ant

== Environment Variables ==
The build environment is the name for the shell in that the application is build. The shell is prepared by exporting a series of environment variables that then are picked up by the build scripts.
<syntaxhighlight lang="bash">
export ADIR=/opt/android
export ANDROID_NDK=$ADIR/android-ndk-r10e
# note the _ROOT postfix here, different pattern
export ANDROID_SDK_ROOT=$ADIR/android-sdk-linux
export Qt5_android=$ADIR/Qt5.5.0/5.5/android_armv7/
export PATH=$ADIR/android-sdk-linux/platform-tools/:$PATH
# adapt the following path to your ant installation
export ANT=/usr/bin/ant
# adapt the following path to your openjdk location, eg:
#  openSUSE: /usr/lib64/jvm/java (needs default version being properly set, see notes below)
#  Debian: /usr/lib/jvm/java-7-openjdk-amd64
export JAVA_HOME=/usr/lib/jvm/java-7-openjdk/
</syntaxhighlight>

'''Some notes:'''
* /opt/android should be replaced with the custom build folder selected by you
* Java platform 7 is needed (both JRE and JDK). One can select the Java platform versions e.g. with <code>update-alternatives --config java</code> and <code>update-alternatives --config javac</code>
* Use <code>jrunscript -e 'java.lang.System.out.println(java.lang.System.getProperty("java.home"));'</code> to find the JAVA_HOME

== Android Emulator for Unit Tests ==
For running unit tests, especially on a CI, either one can run the tests in an emulator or on a physical device. In the following, we explain how to create an AVD (Android Virtual Device) and how to start the emulator from the Android SDK.

==== Create AVD (Android Virtual Device) ====
Within this device, the unit tests are executed. For this we use the AVD Manager:
* Check available targets:
<syntaxhighlight lang="bash">
$ANDROID_SDK_ROOT/tools/android list targets
</syntaxhighlight>
* Create AVD (directly tell to not use custom hardware profile):
<syntaxhighlight lang="bash">
echo no | $ANDROID_SDK_ROOT/tools/android create avd --name myandroid22 -t "android-22" --abi "default/armeabi-v7a"
</syntaxhighlight>
These commands should have created an AVD called '''myandroid22'''. You can check all available AVDs:
<syntaxhighlight lang="bash">
$ANDROID_SDK_ROOT/tools/android list avd
</syntaxhighlight>

==== Start Emulator ====
Running the emulator in a headless mode (without display):
<syntaxhighlight lang="bash">
$ANDROID_SDK_ROOT/tools/emulator64-x86 -avd myandroid22 -no-skin -no-audio -no-window
</syntaxhighlight>
* The '-no-skin' option removes the emulator buttons such as the home and other hardware keyboard buttons.
*  The '-no-audio' option disables the audio support.
*  The '-no-window' option disables the emulator's graphical window display.

==== Further Reading ====
* AVD command line Documentation: http://developer.android.com/tools/devices/managing-avds-cmdline.html
* Emulator Documentation: http://developer.android.com/tools/help/emulator.html
* Emulator tutorial: http://developer.android.com/tools/devices/emulator.html