SketchUp API: How to add a check box to a menu item

Question

I don't see it anywhere in the Ruby API documentation but just in case I'm missing something...

I'm writing a plugin for SketchUp and I'm trying to add some options to the menu bar. One of my options would work best as a checkbox, but right now I have to have two separate buttons. Is there a way to create a checkbox menu item with the Ruby API?

Here's what I had to do instead:

foo = true
UI.menu("Plugins").add_item("Turn foo_option on") { @foo = true }
UI.menu("Plugins").add_item("Turn foo_option off") { @foo = false }

...and then I just use foo to change the options. Is there a cleaner way to do this?

Answer 1

SketchUp can have check marks in menu items. Both menu items and commands can have a validation proc. The documentation for set_validation_proc gives this example:

plugins_menu = UI.menu("Plugins")
item = plugins_menu.add_item("Test") { UI.messagebox "My Test Item"}
status = plugins_menu.set_validation_proc(item)  {
  if Sketchup.is_pro?
   MF_ENABLED
  else
   MF_GRAYED
  end
}

Although for checkmarks you would use the constants MF_CHECKED and MF_UNCHECKED

http://www.sketchup.com/intl/en/developer/docs/ourdoc/menu#set_validation_proc

http://www.sketchup.com/intl/en/developer/docs/ourdoc/command#set_validation_proc