PropertyList

PropertyList is a mutable list of ViewModel items.

Use it to manage repeating data collections from scripts (for example, menu items, inventory entries, or dynamic UI rows). A PropertyList supports:

• Reading item count via length
• 1-based indexed access (list[1], list[2], …)
• Mutations (push, insert, swap, pop, shift, clear)
• Change notifications via addListener and removeListener

For a complete working example, see the Scripting Lists demo.

Fields

length

The current number of items in the list.

function handleSwap(self: MenuListController)
  if self.menu and self.menu.length >= 2 then
    self.menu:swap(1, 2)
  end
end

addListener

Adds a listener that is called when the list changes.

function init(self: MenuListController, context: Context): boolean
  local vmi = context:rootViewModel() :: Data.Main
  if vmi then
    self.menu = vmi.menu
    self.listChanged = listChanged

    self.menu:addListener(self.listChanged)
  else
    print('[MenuListController] Warning: Could not find Main ViewModel.')
  end

  return true
end

removeListener

Removes a previously added list-change listener.

function handleRemoveListener(self: MenuListController)
  if self.menu and self.listChanged then
    self.menu:removeListener(self.listChanged)
  end
end

Methods

push

push(vm: ViewModel) -> ()

Get the list item by index.

function setItemLabel(menu: PropertyList, index: number, label: string)
  if index >= 1 and index <= menu.length then
    local item = menu[index] :: Data.Button
    local itemLabel = item:getString('label')
    if itemLabel then
      itemLabel.value = label
    end
  end
end

Adds a view model to the end of the list.

function addButton(menu: PropertyList, label: string)
  local buttonVm = Data.Button.new()

    local buttonLabel = buttonVm:getString('label')
    if buttonLabel then
      buttonLabel.value = label
    end

    menu:push(buttonVm)
end

insert

insert(vm: ViewModel, index: number) -> ()

Inserts a view model at the given index.

function insertAt(menu: PropertyList, label: string, index: number)
  local buttonVm = Data.Button.new()

  local buttonLabel = buttonVm:getString('label')
  if buttonLabel then
    buttonLabel.value = label
  end

  local insertIndex = math.max(1, math.min(index, menu.length + 1))
  menu:insert(buttonVm, insertIndex)
end

swap

swap(index1: number, index2: number) -> ()

Swaps the positions of the view models at index1 and index2.

function swapItems(menu: PropertyList, index1: number, index2: number)
  local highestIndex = math.max(index1, index2)

  if menu and menu.length >= highestIndex then
    menu:swap(index1, index2)
  end
end

pop

pop() -> ViewModel?

Removes and returns the last view model in the list.

function handlePop(self: MenuListController)
  if self.menu then
    self.menu:pop()
  end
end

shift

shift() -> ViewModel?

Removes and returns the first view model in the list.

function handleShift(self: MenuListController)
  if self.menu then
    self.menu:shift()
  end
end

clear

clear() -> ()

Removes all view models from the list.

function handleClearItems(self: MenuListController)
  if self.menu then
    self.menu:clear()
  end
end

remove

remove(viewModel: ViewModel) -> ()

Removes a view model from the list.

removeAllOf

removeAllOf(viewModel: ViewModel) -> ()

Removes every list entry that references the given view model instance.

removeAt

removeAt(index: number) -> ()

Removes the view model at the given 1-based index from the list.