I do not know the answer for certain, but have you tried the browser/invoke download option?
Just tried it right now, with this event action: Invoke download of TEXTVARIABLE with filename "Level"
...but I'm getting a 404 error: "The requested filename could not be found. You may have closed the project you were previewing in Construct 2."
Judging by the second part of the error, it might have to do with the fact that I'm previewing over LAN on my android device... I'll try to build an .apk and see if it works like that.