Simple AppleScript progress bar demo for Yosemite

progressBar.applescript

set progress description to "A simple progress indicator"
set progress additional description to "Preparing…"
set progress total steps to -1
 
delay 5
 
set progress total steps to 100
repeat with i from 1 to 100
	try
		set progress additional description to "I am on step " & i
		set progress completed steps to i
		delay 0.2
	on error thisErr
		display alert thisErr
		exit repeat
	end try
end repeat

I am using the progress bar in an applescript project. However when using this in a droplet (.app) there is an issue that the progress does not disappear anymore when the droplet is not exiting. Any idea to make it disappear?

I tried:
setting all items to 0, false, null .... the progress just stays in the screen in the background.

Does the value of -1 that progress total steps is initialized to have some special meaning?

@RobLewis, it looks from my experimentation that the -1 is what makes it show the progress indicator as intdeterminate. When running in the Script Editor, this makes it a spinny thingy (instead of a pie), and when it's an Application, it shows the progress bar filled solid when total steps is at -1 (instead of showing one at 0%). I think it's what you would do when you're doing some kind of startup work (especially when you don't know how long it'll take) before you enter your main processing loop.