Flash AS3教程：Direction类和Dot类

CODE:
package index.base.game{

import flash.events.EventDispatcher;
import flash.events.KeyboardEvent;
import flash.events.Event;
import flash.display.InteractiveObject;

import index.base.events.DirectionEvent;

public class Direction extends EventDispatcher{

//方向表示
public static const UP:uint = 0;
public static const DOWN:uint = 1;
public static const LEFT:uint = 2;
public static const RIGHT:uint = 3;

//作用区域
public var area:InteractiveObject;
//是否单向
public var sole:Boolean;

//上下左右键值
private const directionAr:Array = new Array(4);

//是否上下左右
private var _up:Boolean = false;
private var _down:Boolean = false;
private var _left:Boolean = false;
private var _right:Boolean = false;

public function Direction(_area:InteractiveObject,isSole:Boolean = false,_up:uint = 38,_down:uint = 40,_left:uint = 37,_right:uint = 39){
area = _area;
sole = isSole;
directionAr[UP] = _up;
directionAr[DOWN] = _down;
directionAr[LEFT] = _left;
directionAr[RIGHT] = _right;
start();
}

//开始获取事件
public function start():void{
area.addEventListener(KeyboardEvent.KEY_DOWN,onKeyDown);
area.addEventListener(KeyboardEvent.KEY_UP,onKeyUp);
area.addEventListener(Event.ENTER_FRAME,onEnterFrame);
}

//事件帧频繁触发
private function onEnterFrame(e:Event):void{
var num:uint = Number(_up) Number(_down) Number(_left) Number(_right);
if(num == 0){
return;
}

var eve:DirectionEvent = new DirectionEvent(DirectionEvent.DO);
eve.up = _up;
eve.down = _down;
eve.left = _left;
eve.right = _right;
dispatchEvent(eve);
}

//停止获取事件
public function stop():void{
area.removeEventListener(KeyboardEvent.KEY_DOWN,onKeyDown);
area.removeEventListener(KeyboardEvent.KEY_UP,onKeyUp);
area.removeEventListener(Event.ENTER_FRAME,onEnterFrame);