GuiDataSource

GuiDataSource

Description

Data source for UI elements. Holds dynamic data and allows configuration of accessors.

Functions

• addChangeListener
• getCount
• getItem
• iterateRange
• new
• notifyChange
• removeChangeListener
• setData
• setItem

addChangeListener

Description

Add a listener with a member function which is called when this data source changes.

Definition

addChangeListener()

Arguments

any	target
any	callback

Code

function GuiDataSource:addChangeListener(target, callback)
    self.changeListeners[target] = callback or NO_CALLBACK
end

getCount

Description

Get the number of data items.

Definition

getCount()

Code

function GuiDataSource:getCount()
    return # self.data
end

getItem

Description

Get a data item at a given index.

Definition

getItem()

Arguments

any	index

Code

function GuiDataSource:getItem(index)
    return self.data[index]
end

iterateRange

Description

Iterate a data range within the given indices. This is an iterator factory compatible with the default Lua for loop. E.g. "for _, item in source:iterateRange(1, 10) do" will loop over data items 1 to 10.

Definition

iterateRange()

Arguments

any	startIndex
any	endIndex

Code

function GuiDataSource:iterateRange(startIndex, endIndex)
    local iterator = function (data, iter)
        local item = data[iter]
        if iter < = endIndex and item ~ = nil then
            return iter + 1 , item
        else
                return nil , nil
            end
        end

        return iterator, self.data, startIndex
    end

new

Description

Create a new GuiDataSource instance.

Definition

new()

Arguments

any	subclass_mt

Code

function GuiDataSource.new(subclass_mt)
    local self = setmetatable( { } , subclass_mt or GuiDataSource _mt)

    self.data = NO_DATA
    self.changeListeners = { } -- {<listener table> = <listener function>}

        return self
    end

notifyChange

Description

Notify this data source that its data has been changed externally. This will call the change callback if it has been set.

Definition

notifyChange()

Code

function GuiDataSource:notifyChange()
    for target, callback in pairs( self.changeListeners) do
        callback(target)
    end
end

removeChangeListener

Description

Remove a previously added change listener from the notification table.

Definition

removeChangeListener()

Arguments

any	target

Code

function GuiDataSource:removeChangeListener(target)
    self.changeListeners[target] = nil
end

setData

Description

Set the data source data array.

Definition

setData()

Arguments

any	data

Code

function GuiDataSource:setData(data)
    self.data = data or NO_DATA
    self:notifyChange()
end

setItem

Description

Set a data item at a given index. If the index is out bounds of the data, this will have no effect.

Definition

setItem()

Arguments

any	index
any	value
any	needsNotification

Code

function GuiDataSource:setItem(index, value, needsNotification)
    if index > 0 and index < = # self.data then
        self.data[index] = value
        if needsNotification then
            self:notifyChange()
        end
    end
end