How to open Slidable by triggering a function.

[mhdshibin]

I want to open slidable using an onPressed by implementing a gestureDetector as the child of Slidable. I am doing this because sometimes the "Slidable" action is not apparent to the user. So if the user tries to tap or press-and-hold on the child widget. I wish to expand the Slidable and show the user that such a feature exists.