JRE

Android

This is a set of projects (bindings, code generator, examples and more) that enables developers to write ROS2 applications for the JVM and Android.

Besides this repository itself, there's also:

• https://github.com/esteve/ament_java, which adds support for Gradle to Ament
• https://github.com/esteve/ament_gradle_plugin, a Gradle plugin that makes it easier to use ROS2 in Java and Android project. The Gradle plugin can be installed from Gradle Central https://plugins.gradle.org/plugin/org.ros2.tools.gradle
• https://github.com/esteve/ros2_java_examples, examples for the Java Runtime Environment
• https://github.com/esteve/ros2_android_examples, examples for Android

No, any language that targets the JVM can be used to write ROS2 applications.

Yep! Make sure to use Fast-RTPS as your DDS vendor and at least this revision.

The current set of features include:

• Generation of all builtin and complex ROS types, including arrays, strings, nested types, constants, etc.
• Support for publishers and subscriptions
• Tunable Quality of Service (e.g. lossy networks, reliable delivery, etc.)
• Clients and services
• Timers
• Composition (i.e. more than one node per process)
• Time handling (system and steady, ROS time not yet supported ros2/ros2#350)
• Support for Android
• Parameters services and clients (both asynchronous and synchronous)

First of all, download the ament repositories in a separate workspace:

mkdir -p ~/ament_ws/src
cd ~/ament_ws
wget https://raw.githubusercontent.com/esteve/ament_java/master/ament_java.repos
vcs import ~/ament_ws/src < ament_java.repos
src/ament/ament_tools/scripts/ament.py build --symlink-install --isolated

We need to split the build process between Ament and the rest of ros2_java workspace so that the additional build type for Gradle projects is picked up by Ament.

Make sure you have Gradle 3.2 (or later) installed. Ubuntu 16.04 ships with Gradle 2.10, you can install a more recent version of Gradle from the following PPA:

$ sudo add-apt-repository ppa:cwchien/gradle
$ sudo apt install -y gradle

The following sections deal with building the ros2_java codebase for the desktop Java runtime and for Android.

mkdir -p ~/ros2_java_ws/src
cd ~/ros2_java_ws
wget https://raw.githubusercontent.com/esteve/ros2_java/master/ros2_java_desktop.repos
vcs import ~/ros2_java_ws/src < ros2_java_desktop.repos
. ~/ament_ws/install_isolated/local_setup.sh
ament build --symlink-install --isolated

Now you can just run a bunch of examples, head over to https://github.com/esteve/ros2_java_examples for more information.

The Android setup is slightly more complex, you'll need the SDK and NDK installed, and an Android device where you can run the examples.

Make sure to download at least the SDK for Android Lollipop (or greater), the examples require the API level 21 at least and NDK 14.

You may download the Android NDK from the official website, let's assume you've downloaded 15c (the latest stable version as of 2017-11-07) and you unpack it to ~/android_ndk

We'll also need to have the Android SDK installed, for example, in ~/android_sdk and set the ANDROID_HOME environment variable pointing to it.

Although the ros2_java_android.repos file contains all the repositories for the Android bindings to compile, we'll have to disable certain packages (python_cmake_module, rosidl_generator_py, test_msgs) that are included the repositories and that we either don't need or can't cross-compile properly (e.g. the Python generator)

export ANDROID_HOME=$HOME/android_sdk
mkdir -p ~/ros2_android_ws/src
cd ~/ros2_android_ws
wget https://raw.githubusercontent.com/esteve/ros2_java/master/ros2_java_android.repos
vcs import ~/ros2_android_ws/src < ros2_java_android.repos
. ~/ament_ws/install_isolated/local_setup.sh
ament build --isolated --skip-packages python_cmake_module rosidl_generator_py test_msgs \
  --cmake-args \
  -DPYTHON_EXECUTABLE=/usr/bin/python3 \
  -DCMAKE_TOOLCHAIN_FILE=$HOME/android_ndk/android-ndk-r15c/build/cmake/android.toolchain.cmake \
  -DANDROID_FUNCTION_LEVEL_LINKING=OFF \
  -DANDROID_NATIVE_API_LEVEL=android-21 \
  -DANDROID_TOOLCHAIN_NAME=arm-linux-androideabi-clang \
  -DANDROID_STL=gnustl_shared \
  -DANDROID_ABI=armeabi-v7a \
  -DANDROID_NDK=$HOME/android_ndk/android-ndk-r15c \
  -DTHIRDPARTY=ON \
  -DCOMPILE_EXAMPLES=OFF \
  -DCMAKE_FIND_ROOT_PATH="$HOME/ament_ws/install_isolated;$HOME/ros2_android_ws/install_isolated" \
  -- \
  --parallel \
  --ament-gradle-args \
  -Pament.android_stl=gnustl_shared -Pament.android_abi=armeabi-v7a -Pament.android_ndk=$HOME/android_ndk/android-ndk-r15c --

You can find more information about the Android examples at https://github.com/esteve/ros2_android_examples