Difference between revisions of "EventDispatcher:addEventListener"

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m (formatting)
 
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=== Description ===
 
=== Description ===
 
Registers a listener function and an optional data value so that the listener function is called when an event of a particular type occurs.
 
Registers a listener function and an optional data value so that the listener function is called when an event of a particular type occurs.
<source lang="lua">
+
<syntaxhighlight lang="lua">
 
EventDispatcher:addEventListener(type,listener,data)
 
EventDispatcher:addEventListener(type,listener,data)
</source>
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</syntaxhighlight>
  
 
=== Parameters ===
 
=== Parameters ===
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'''listener''': (function) the listener function that processes the event<br/>
 
'''listener''': (function) the listener function that processes the event<br/>
 
'''data''': (any) an optional data parameter that is passed as a first argument to the listener function '''optional'''<br/>
 
'''data''': (any) an optional data parameter that is passed as a first argument to the listener function '''optional'''<br/>
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 +
=== Example ===
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<syntaxhighlight lang="lua">
 +
local function callback(data, e)
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data = data or {}
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data.source = data.source or Pixel.new(0x00ff00, 1, 64, 64)
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data.source.sx = data.source.sx or 1
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data.source.sy = data.source.sy or 1
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local x = e.touch.x
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local y = e.touch.y
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end
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 +
local pix = Pixel.new(0xff00ff, 1, 64, 64)
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pix.sx = pix:getScaleX()
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pix.sy = pix:getScaleY()
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 +
stage:addChild(pix)
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stage:addEventListener(Event.TOUCHES_END, callback, { source=pix, }) -- type,listener,data
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</syntaxhighlight>
  
 
{{EventDispatcher}}
 
{{EventDispatcher}}

Latest revision as of 02:06, 7 December 2025

Available since: Gideros 2011.6
Class: EventDispatcher

Description

Registers a listener function and an optional data value so that the listener function is called when an event of a particular type occurs.

EventDispatcher:addEventListener(type,listener,data)

Parameters

type: (string) the type of event
listener: (function) the listener function that processes the event
data: (any) an optional data parameter that is passed as a first argument to the listener function optional

Example

local function callback(data, e)
	data = data or {}
	data.source = data.source or Pixel.new(0x00ff00, 1, 64, 64)
	data.source.sx = data.source.sx or 1
	data.source.sy = data.source.sy or 1
	local x = e.touch.x
	local y = e.touch.y
end

local pix = Pixel.new(0xff00ff, 1, 64, 64)
pix.sx = pix:getScaleX()
pix.sy = pix:getScaleY()

stage:addChild(pix)
stage:addEventListener(Event.TOUCHES_END, callback, { source=pix, }) -- type,listener,data