publisher and subscriber in rosjava

asked 2013-11-15 16:19:43 -0600

This post is a wiki. Anyone with karma >75 is welcome to improve it.

I am trying to follow the publisher/subscriber tutorial for rosjava provided at this link.

http : //rosjava.github.io/rosjava_core/latest/getting_started.html#creating-a-new-java-package

However, when i copy paste the code into a file in my project, I am getting compilation errors like (1)package std_msgs does not exist and 2)cannot find symbol) when i build my package with catkin_make. I am using catkin_make for building because this tutorial says so: --http ://wiki.ros.org/rosjava_build_tools/Tutorials/hydro/Creating%20Rosjava%20Packages

I added my dependencies (rosjava_bootstrap,rosjava_build_tools,std_msgs,rosjava_messages) in my package.xml file like this.(i think i should be doing this in the gradle file)

<build_depend>rosjava_build_tools</build_depend> <run_depend>rosjava_build_tools</run_depend>

How do I add the dependencies for the modules being imported in the begining of the publisher program. the modules are-

import org.ros.namespace.GraphName; import org.ros.node.Node; import org.ros.node.NodeMain;

Can somebody tell me how to add the dependencies?

Comments

I am using ROS hydro.

uzair ( 2013-11-15 16:48:01 -0600 )edit

So you create a package following the second tutorial, and then you add the code from the first one? right? Can you just follow the second tutorial and compile without errors?

jorge ( 2013-11-17 13:03:11 -0600 )edit

I couldnt find any code for publisher or subscriber for the second tutorial using catkin_make for building. I am pretty sure i need to add the dependencies in the gradle file but i dont know how. I read the gradle tutorial where it says i need to specify the version of the package too. How do i specify these packages [.org.ros.namespace.GraphName; org.ros.node.Node; org.ros.node.NodeMain]according to the syntax given here for dependencies [http://www.gradle.org/docs/current/userguide/tutorial_java_projects.html]-go to example 7.4;

uzair ( 2013-11-17 16:42:24 -0600 )edit

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answered 2013-11-18 01:05:21 -0600

jorge

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Yes, I think so; you add dependencies on build.gradle file. An example:

dependencies {
    compile 'org.ros.rosjava_core:rosjava:[0.1,0.2)'
    compile 'org.ros.rosjava_messages:std_msgs:[0.5,0.6)'
}

not sure if this will work or you need something more.

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Comments

There are two build.gradle files. One in my package folder and one inside the project folder in my package folder. In which build.gradle file do i add this?

uzair ( 2013-11-26 14:50:11 -0600 )edit

Not fully sure what you mean with project and package... I think the one in project. Must have almost no additional contents. The one in the package contains some groovy functions.

jorge ( 2013-11-26 15:34:36 -0600 )edit

I created a pakcage called rosjava_foo and in that i created a project called dude as it is said in the tutorial. THere is one build.gradle in the rosjava_foo folder and one in the dude folder. The one in the dude folder has a section called "dependencies{ } " but it is commented between /* and */. The build.gradle in hte package folder has some commands like apply plugin etc along with the maven repository and the dependency block.

uzair ( 2013-11-26 15:48:10 -0600 )edit

Right; add dependencies to the one in the dude folder. Please mark the question as answered if it works to help others with the same problem.

jorge ( 2013-11-26 16:53:11 -0600 )edit

i added compile 'org.ros.rosjava_core:rosjava:[0.1,)' and the errors reduced from from 20 to 1. The error I have now states that "GraphName(java.lang.String) has private access in org.ros.namespace.GraphName return new GraphName("rosjava_tutorial_pubsub/listener")

uzair ( 2013-11-26 17:45:57 -0600 )edit

mmm... good improvement! Tutorial must be outdated; replace new GraphName("rosjava_tutorial_pubsub/listener") with GraphName.of("rosjava_tutorial_pubsub/listener")

jorge ( 2013-11-26 17:58:28 -0600 )edit

All works now? Please mark question as solved if so

jorge ( 2013-11-28 21:12:18 -0600 )edit

If I do that then i get a new error. It says symbol not defined and the arrow points to the dot in GraphName.of .Appreciate all the help.

uzair ( 2013-12-26 16:12:23 -0600 )edit

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