ros2，colcon build 报错

[2449154969]

By not providing "Findexample_ros2_interfaces.cmake" in CMAKE_MODULE_PATH
this project has asked CMake to find a package configuration file provided
by "example_ros2_interfaces", but CMake did not find one.

Could not find a package configuration file provided by
"example_ros2_interfaces" with any of the following names:

example_ros2_interfacesConfig.cmake
example_ros2_interfaces-config.cmake

Add the installation prefix of "example_ros2_interfaces" to
CMAKE_PREFIX_PATH or set "example_ros2_interfaces_DIR" to a directory
containing one of the above files. If "example_ros2_interfaces" provides a
separate development package or SDK, be sure it has been installed.

[Lorry]

@2449154969 在 ros2，colcon build 报错 中说：

Could not find a package configuration file provided by
"example_ros2_interfaces" with any of the following names:

你当前的环境变量没有example_ros2_interfaces这个包，把那个包激活以后再编译