run the roslaunch comman in Qt creator

edit

I tried to run the roslaunch command in Qt but the error is:

sh: 1: /opt/ros/indigo/bin/roslaunch/roslaunch: not found

and I tried to download the plugin for ROS it still doesn't work.

and here is my code:

QProcess * exec;
exec =new QProcess(this);
exec->setProcessChannelMode(QProcess::MergedChannels);
//exec->start("gnome-terminal", QStringList()<<"source ~/catkin_ws/devel/settup.bash; roslaunch p2os_launch pioneer_joy_drive.launchS ")
QString command = "/opt/ros/indigo/bin/roslaunch/roslaunch p2os_launch pioneer_joy_drive.launch";
exec->start(command);
system(qPrintable(command));