content: sub Init() 
      m.top.backgroundColor = "0x662D91"
      m.top.backgroundUri = "pkg:/images/background.jpg"
      m.loadingIndicator = m.top.FindNode("loadingIndicator")
  
      InitScreenStack()
      ShowGridScreen()
      RunContentTask()
  end sub
  
  function OnKeyEvent(key as String, press as Boolean) as Boolean 
      result = false
  
      if press
          
          if key = "back" ' back button event listener
              numberOfScreens = m.screensStack.count()
  
              if numberOfScreens > 1
                  CloseScreen(Invalid) ' screen stack logic
                  result = true
              end if
          end if
      end if
  
      return result
  end function