ttk::progressbar example

package require Tk 

proc timer {widget seconds} {
    toplevel $widget
    ttk::progressbar $widget.pb1 -orient horizontal -mode determinate -maximum $seconds
    grid $widget.pb1
    update idletasks

    # Do some real work here for $seconds seconds
    for {set i 0} {$i < $seconds} {incr i} {
	after 1000 ;# Just waiting in this example, might as well do something useful here
	$widget.pb1 step ;# After some part of the work, advance the progressbar
	update idletasks;# Needed to update the progressbar
    }

    # Done, clean up the dialog and progressbar
    destroy $widget
}

pack [button .b1 -text "Upgrade" -command { timer .new 10 }]