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flash.events Package Summary

The ActionScript 3.0 event model, which follows the DOM Level 3 Events specification.

EventDispatcher

The base class for all classes that dispatch events. It allows any object on the display list to be an event target.

Key Methods

  • addEventListener(type:String, listener:Function, useCapture:Boolean = false, priority:int = 0, useWeakReference:Boolean = false):void
    • useCapture: If true, listener handles the event during the capture phase.
    • priority: Higher numbers are executed first.
    • useWeakReference: If true, the listener does not prevent the target from being garbage collected.
  • removeEventListener(type:String, listener:Function, useCapture:Boolean = false):void
  • dispatchEvent(event:Event):Boolean: Dispatches an event into the event flow.
  • hasEventListener(type:String):Boolean: Checks if a listener is registered.
  • willTrigger(type:String):Boolean: Checks if a listener is registered on this object or any ancestor.

Event

The base class for event objects passed to listeners.

Properties

Property Type Description
type String The name of the event (case-sensitive).
target Object The object that dispatched the event (the "origin").
currentTarget Object The object currently processing the event (the "listener").
eventPhase uint 1: Capture, 2: Target, 3: Bubbling.
bubbles Boolean Whether the event moves back up the display list.
cancelable Boolean Whether preventDefault() can be called.

Methods

  • stopPropagation():void: Prevents the event from moving to the next node in the flow.
  • stopImmediatePropagation():void: Prevents other listeners on the current node from executing.
  • preventDefault():void: Cancels the default behavior associated with the event (if cancelable is true).
  • clone():Event: Returns a copy of the event (required for custom events).

Common Event Types

  • Event.ADDED_TO_STAGE: Dispatched when a display object is added to the stage.
  • Event.REMOVED_FROM_STAGE: Dispatched when a display object is removed.
  • Event.ENTER_FRAME: Dispatched at the beginning of every frame.
  • Event.COMPLETE: Dispatched when a load operation finishes.
  • Event.CHANGE: Dispatched when a control (like a text field) changes.

MouseEvent (Extends Event)

Dispatched when a mouse/pointer interaction occurs.

Key Properties

  • localX, localY: Coordinates relative to the target.
  • stageX, stageY: Coordinates relative to the Stage (global).
  • buttonDown: Whether the primary button is pressed.
  • altKey, ctrlKey, shiftKey: Whether modifier keys are pressed.

Common Types

  • MouseEvent.CLICK, DOUBLE_CLICK
  • MouseEvent.MOUSE_DOWN, MOUSE_UP
  • MouseEvent.MOUSE_OVER, MOUSE_OUT, ROLL_OVER, ROLL_OUT
  • MouseEvent.MOUSE_MOVE

KeyboardEvent (Extends Event)

Dispatched when keyboard interaction occurs.

Key Properties

  • keyCode: Numeric code for the key (e.g., Keyboard.SPACE).
  • charCode: Numeric character code (e.g., 65 for 'A').
  • keyLocation: Location (Standard, Left, Right, NumPad).

Common Types

  • KeyboardEvent.KEY_DOWN
  • KeyboardEvent.KEY_UP

Example: Event Handling

import flash.events.MouseEvent;

myButton.addEventListener(MouseEvent.CLICK, onClick);

function onClick(event:MouseEvent):void {
    trace("Clicked at: " + event.stageX + ", " + event.stageY);
    // target is myButton
    // currentTarget is whatever object added the listener
}