Livecode player: How to catch up a "dragStop" message

Question

Within a player, I would like to allow the user to manually drag the boundaries of the selection (start time and end time). I can use a dragStart message to catch if the user start to drag, but I can't get the final positions of the elements, because I don't know when the user stop to drag.

I have tried something like this:

on dragStart
   repeat until the mouse is up
       /*unfortunately, this part freeze the player*/
   end repeat
   put the timeScale of me into sr
   put the endTime of me into endT
   put endT/sr
end dragStart

But the player is frozen with the wait command. So the user can't move the boundaries, and I can't get the final position of the "endTime".

How to wait until the mouse is up, but without frozen the player?

Answer 1

This could finally be achieved with a very simple code (as often with livecode):

on selectionchanged
     put the timeScale of me into sr
     put the endTime of me into endT
     put endT/sr into fld 1
end selectionchanged

Answer 2

There are many ways to get out of that blocking loop, waiting "with messages" or sending a message in time within a handler, which releases the engine during the interval. But the most basic might be something like this, if you will try an experiment. Make a button and a field on a new card. In the button script:

on dragStart
put the loc of me into line 1 of fld 1
end dragStart

on mouseMove
if the mouseLoc is within the rect of me and the mouse is down then
set the loc of me to the mouseLoc
end if
end mouseMove

on mouseup
 put the loc of me into line 2 of fld 1
end mouse up

Now this is overdone, but at least shows how you can use small handlers to deal with small issues.