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johnmarsden's avatar
johnmarsden
Visitor
9 years ago

Accessing global functions in SceneGraph components?

Hey there,

How do you access global functions from within Scene Graph *.brs files? I have a utility class that has things like toString(), getScreenHeight(), etc that I want to access. 
' source/utility/general.brs

function toString(var)
   return ...
end function



There's a component being included called Menu.xml, which reaches out to a Menu.brs class that has a "init()" function. I've tried things like 
m.global.toString("test")
m.top.toString("test")
m.toString("test")
toString("test")


But none of it works. What's the best approach for accessing global utility functions from within components?
Thanks!
Roku Developer Program

11 Replies

  • tmat1075's avatar
    tmat1075
    Visitor
    9 years ago
    What I've been doing is add an extra "script" tag to each of the xml files. 

    <?rokuml version="1.0" encoding="utf-8" ?>

    <!-- a Task handling the playback loop of both content abd ad -->
    <component name="PlayerTask" extends="Task">

      <script type="text/brightscript" uri="pkg:/components/PlayerTask.brs" />
      <script type="text/brightscript" uri="pkg:/components/Helpers/VideoHelpers.brs"/>

      <interface>
          <field id="video" type="node" />
      </interface>

    </component> 
  • destruk's avatar
    destruk
    Streaming Star
    9 years ago
    Copying the function you need into the component/duplicating it works.
  • NB_'s avatar
    NB_
    Roku Guru
    9 years ago
    Currently you cannot share global/utility functions between different components. There have been multiple requests to make that possible, keep asking and hopefully that will happen.

    The workaround in use is duplicating code - whether literally or including via <script .../>, which leads to the same code being compiled/baked separately in each component. Please beware that using this too liberally may notably slow your components or launch times.
  • johnmarsden's avatar
    johnmarsden
    Visitor
    9 years ago
    What's the cost of passing references from an instantiated object to each component? I have an instantiated class called "String" that i want to pass to components by reference. I'm assuming this wont be too damaging or resource consuming correct? Will BrightScript duplicate referenced objects if passed to a component even though they aren't re instantiated?
  • NB_'s avatar
    NB_
    Roku Guru
    9 years ago
    "johnmarsden" wrote:
    What's the cost of passing references from an instantiated object to each component? I have an instantiated class called "String" that i want to pass to components by reference. I'm assuming this wont be too damaging or resource consuming correct? Will BrightScript duplicate referenced objects if passed to a component even though they aren't re instantiated?

    Not sure i understand the question. By "instantiated class" do you mean a roAssociativeArray object with values and functions in it? If so, please note that RSG currently does not support functions inside component fields. See a list of what is supported here https://sdkdocs.roku.com/display/sdkdoc ... Attributes
    The unsupported elements - in this case functions - would just be silently stripped away.
  • johnmarsden's avatar
    johnmarsden
    Visitor
    9 years ago
    Ah yes, I'm seeing that now. Stripped away after passing them in 😞  That's unfortunate.
  • Tyler_Smith's avatar
    Tyler_Smith
    Streaming Star
    9 years ago
    Something we've been doing is storing a Utility component in the global scope and exposing our utilities via functional fields.

    You can see how to add functional fields to a component here:
    https://sdkdocs.roku.com/display/sdkdoc ... onalFields


    Sample implementation/call:

    m.global.addFields({
      Utilities: CreateObject("UtilityComponent")
    })




    m.global.Utilities.callFunc("myFunction", {})
  • georgejecook's avatar
    georgejecook
    Streaming Star
    8 years ago
    @tylersmith - you sir, rock!

    I had missed functional fields, and their wonderful promise until I saw this - THANKS.