IndexChangeSubjectMixin

IndexChangeSubjectMixin

Description

Add this mixin to a GuiElement to implement an observer pattern for index changes (e.g. paging, options, lists).

Parent

GuiMixin

Functions

• addIndexChangeObserver
• addTo
• clone
• new
• notifyIndexChange

addIndexChangeObserver

Description

Add an index change observer with a callback.

Definition

addIndexChangeObserver(guiElement Decorated, observer Observer, indexChangeCallback Function(observer,)

Arguments

guiElement	Decorated	GuiElement instance which has received this method
observer	Observer	object instance
indexChangeCallback	Function(observer,	index, count), where index is the new index and count the current number of indexable items

Code

function IndexChangeSubjectMixin.addIndexChangeObserver(guiElement, observer, indexChangeCallback)
    guiElement[ IndexChangeSubjectMixin ].callbacks[observer] = indexChangeCallback
end

addTo

Description

See GuiMixin:addTo()

Definition

addTo()

Arguments

any	guiElement

Code

function IndexChangeSubjectMixin:addTo(guiElement)
    if IndexChangeSubjectMixin:superClass().addTo( self , guiElement) then
        guiElement.addIndexChangeObserver = IndexChangeSubjectMixin.addIndexChangeObserver
        guiElement.notifyIndexChange = IndexChangeSubjectMixin.notifyIndexChange

        return true
    else
            return false
        end
    end

clone

Description

Clone this mixin's state from a source to a destination GuiElement instance.

Definition

clone()

Arguments

any	srcGuiElement
any	dstGuiElement

Code

function IndexChangeSubjectMixin:clone(srcGuiElement, dstGuiElement)
    if srcGuiElement[ IndexChangeSubjectMixin ].callbacks ~ = nil then
        dstGuiElement[ IndexChangeSubjectMixin ].callbacks = table.clone(srcGuiElement[ IndexChangeSubjectMixin ].callbacks)
    end
end

new

Description

Definition

new()

Code

function IndexChangeSubjectMixin.new()
    local self = GuiMixin.new(IndexableElementMixin_mt, IndexChangeSubjectMixin )
    self.callbacks = { } -- {observer = callback}

    return self
end

notifyIndexChange

Description

Notify observers of an index change.

Definition

notifyIndexChange(guiElement Decorated, index New, count Indexable)

Arguments

guiElement	Decorated	GuiElement instance which has received this method
index	New	index
count	Indexable	item count

Code

function IndexChangeSubjectMixin.notifyIndexChange(guiElement, index, count)
    local callbacks = guiElement[ IndexChangeSubjectMixin ].callbacks

    for observer, callback in pairs(callbacks) do
        callback(observer, index, count)
    end
end