Originally from a [http://rymawby.com/brightscript/roku/Exiting-out-of-a-brightscript-scenegraph-app.html](rymawby.com article).
To exit a a SceneGraph application you have to complete executions of your main method. A nice easy way to do this is to observe a field on your scene and then fire a roSGNodeEvent via the port.
You’ve probably got something like the following in your main app brs file.
screen = CreateObject("roSGScreen")
m.port = CreateObject("roMessagePort")
screen.setMessagePort(m.port)
scene = screen.CreateScene("mainScene")
screen.show()
scene.setFocus(true)
while(true)
msg = wait(0, m.port)
msgType = type(msg)
if msgType = "roSGScreenEvent" then
if msg.isScreenClosed() then
return
end if
end if
end while
This would exit out if you clicked back on the RCU when the scene is focused as msg.isScreenClosed() would be true - but what if we wanted to close the app on another event? It’s actually pretty simple to do. The main challenge is exiting out of the while loop. A handy way is to add an observer to the scene and pass the port as the handler.
You could modify this main screen to look something like:
screen = CreateObject("roSGScreen")
m.port = CreateObject("roMessagePort")
screen.setMessagePort(m.port)
scene = screen.CreateScene("mainScene")
screen.show()
scene.observeField("exitApp", m.port)
scene.setFocus(true)
while(true)
msg = wait(0, m.port)
msgType = type(msg)
if msgType = "roSGScreenEvent" then
if msg.isScreenClosed() then
return
else if msgType = "roSGNodeEvent" then
field = msg.getField()
if field = "exitApp" then
return
end if
end if
end if
end while
By adding the observer scene.observeField("exitApp", m.port) on the scene a roSGNodeEvent msg will fire on m.port when we change the exitApp interface field. It’s a nice succinct way of handling this.
Set up your MainScene.xml so it has an observable interface boolean field called exitApp or similar:
<?xml version="1.0" encoding="utf-8" ?>
<component name="MainScene" extends="OverhangPanelSetScene" >
<interface>
<field id="exitApp" type="boolean" value="false" />
</interface>
<children>
</children>
<script type="text/brightscript" uri="pkg://components/MainScene.brs" />
</component>
Then you need to setup your MainScene.brs to alter the exitApp variable on an OK click:
function init() as Void
print "ExitApp"
end function
function onKeyEvent(key as String, press as Boolean) as Boolean
if key = "OK" then
m.top.exitApp = true
end if
end function