Events in BrightScript center around an event loop and the roMessagePort object. Most BrightScript objects can post to a message port in the form of an event object: For example, the roTimer object posts events of the type roTimerEvent when configured intervals are reached.
The following script sets the destination message port using the SetPort() method, waits for an event in the form of an roGpioButton object, and then processes the event.
print "BrightSign Button-LED Test Running"
p = CreateObject("roMessagePort")
gpio = CreateObject("roGpioControlPort")
gpio.SetPort(p)
while true
msg=wait(0, p)
if type(msg)="roGpioButton" then
butn = msg.GetInt()
if butn <=5 then
gpio.SetOutputState(butn+17,1)
print "Button Pressed: ";butn
sleep(500)
gpio.SetOutputState(butn+17,0)
end if
end if
REM ignore buttons pressed while flashing led above
while p.GetMessage()<>invalid
end while
end while
Note that lines 6-7 can be replaced using the following (and substituting end while with end for):
For each msg in p