Can't load message (ERROR: Cannot load message class for [roscopter/Attitude]. Are your messages built?)

[msadowski]

Hi!

I 'm trying to use roscopter with APM. I think I was able to successfully follow the wiki pages for building the package (catkin_make didn't return any errors, catkin_make --pkg roscopter also worked well).

I am able to run the module without any problem, the APM initializes correctly. The problem occures when I try to echo some of the rostopic connected to roscopter, then I get an error:
ERROR: Cannot load message class for [roscopter/Attitude]. Are your messages built?

I could successfully echo /gps message therefore I suspect the problem I have is with roscopter messages.

Do you have any ideas what I might be doing wrong? I am using ros hydro.

[lanyusea]

use rostopic list to check the topic name,

I remember it is not called roscopter/Attitude

[msadowski]

Rostopic name is indeed different from the name of message file. Name of rostopic is /attitude and the mentioned error is what I see when I try to echo it.

[tonybaltovski]

I haven't had that error. Have you tried re-building everything?

[msadowski]

Did that several times. I even tried to delete everything and start from scratch with the same result.

[tonybaltovski]

Does rosmsg show roscopter/attitude show anything? When you make the package does it say it has built the message?

[lanyusea]

@msadowski I haven't meet that issue neither.

I searched some similar questions, most answers say it is the caused by the package is not sourced by ROS.

try editing CmakeList file dependency if necessary and building the project again and sourcing the setup.bash

[msadowski]

Catkin_make says that the messages were built.

Result of rosmsg show roscopter/attitude is:
Unable to load msg [roscopter/attitude]: Cannot locate message [attitude]: unknown package [roscopter] on search path
followed by long list of different paths. So I assume the solution proposed by @lanyusea might work. I'll check it tomorrow and report back. Thanks for your help!