Roku Developer Program

[FCF-Ben]

Trying to mash together two (or three) examples I found, to create a dialog that will fire if you press back arrow when on the home screen (or technically the last screen in the stack array). 

So what I am trying to achieve is a logic along the lines of:

1. Intercept the backarrow key (onkeyevent) 

2. Display dialog for "Confirm Exit" 

3 observeField "buttonSeleted" and set callback to "onButtonSelected"

4. Return true to tell Roku that we handled the backarrow

Then later (buttonSelected)

5. set m.top.exitApp = true (which breaks the while loop and exits the program)

I'm fairly certain step 1-4 is working, but step 5 is never called. (the print to the debug log never happens)

Here is the code:

  sub showExitDialog()
    m.exitDialog = createObject("roSGNode", "Dialog")
    m.exitDialog.backgroundUri = "pkg:/images/dialog-background.png"
    m.exitDialog.title = "Close channel"
    m.exitDialog.buttons = ["Exit", "Cancel"]
    m.exitDialog.optionsDialog = true
    m.exitDialog.message = "Do you want to close Channel"
    m.exitDialog.observeField("buttonSeleted", "onButtonSelected")
    m.top.dialog = m.exitDialog
  end sub

  'detect selection
  sub onButtonSelected()
    'use the exitDialoge Button Selected field
    print "Serring Exit to true"
    if m.exitDialog.buttonSelected = 0 then
        print "Exiting app"
        m.top.exitApp = true
    else
        print "Doing nothing"
    end if
  end sub

And the code to intercept the back arrow

function onKeyEvent (key as String, press as boolean) as boolean
    handled=false
    if press then 
        if (key = "back") then
            handled=true
            print "You pressed back"
            showExitDialog()
      end if
    end if
  return handled
end function

Also, I stole from two different examples, where the first one is 

https://developer.roku.com/en-gb/docs/references/scenegraph/standard-dialog-framework-nodes/standard...

And the second one was how to break the while loop

https://rymawby.com/brightscript/roku/Exiting-out-of-a-brightscript-scenegraph-app.html

Also, the example used observeFieldScoped, but could not find any documentation on what that does. (A bit new to brigthscript, so sorry if that is obvious)

[renojim · Accepted solution]

If the code you've shown is a copy and paste then you have a typo:

m.exitDialog.observeField("buttonSeleted", "onButtonSelected")

Should be buttonSelected.

But that's not the only problem.  Even if you fix the line, add a print in front of it and I bet it prints out false meaning the statement failed and your observer will never be called.

print m.exitDialog.observeField("buttonSelected", "onButtonSelected")

That "buttonSelected" needs to be attached to a component.  I'm not sure how to accomplish that; I've only ever done it via an interface alias in the XML file for the node/group/component or whatever it's called.

XML:

<interface>
   <field id="button_selected"
      type="assocarray"
      alias="dialog.buttonSelected"
   />
</interface>
<children>
   <Dialog
   id="dialog"
   />
</children>
</component> 

BRS:

print m.top.observeField("button_selected", "onButtonSelected")

I tried a quick test trying to add it to the code you have, but I couldn't come up with the right way to specify it or I had some other problem with the code since it's not complete.

As for observeField vs observeFieldScoped, I've wondered the same thing, but I've never taken the time to investigate it.

I have to include my standard caveat:  As I've stated many times, I'm not the person to ask about scene graph as I absolutely hate it.  Maybe if I wasted took the time to learn more than the bare minimum I wouldn't hate it so much, but I don't see that ever happening.

[FCF-Ben]

hank you so very much @renojim 

And sorry for not responding yesterday, did not get a notification that I had a response to my question. 

And yes, I've been staring myself blind trying to figure out what part of the data inheritance structure I just don't understand, should have checked the spelling first 🙂

Thank you so very very much.

Now it works in that the dialog tires to send the message, but the While loop is never broken, and the app does not end.