Hi Peter,
You need another class to monitor the event you raised, which this class have a process method to process this event. It`s same with OO alv, you need define another class to process the double click.
refer this link,
https://help.sap.com/saphelp_nw70/helpdata/en/71/a8a77955bc11d194aa0000e8353423/content.htm
regards,
Archer