题 目:用AS3实再FLASH游戏的上下左右移动

//Key.as：
package CYPL.Game{
import flash.display.InteractiveObject;
import flash.events.KeyboardEvent;
import flash.events.Event;
public class Key {
private static var keyObj:Object;
private static var io:InteractiveObject;
private static var keyTestHandler:Function;
public static function init(io:InteractiveObject,keyTestHandler:Function):void {
Key.io=io;
Key.keyTestHandler=keyTestHandler;
keyObj=new Object ;
io.addEventListener(KeyboardEvent.KEY_DOWN,keyDownHandler);
io.addEventListener(KeyboardEvent.KEY_UP,keyUpHandler);
}
public static function isDown(key:int):Boolean {
return !!keyObj[key];
}
private static function keyDownHandler(e:KeyboardEvent):void {
keyObj[e.keyCode]=true;
io.addEventListener(Event.ENTER_FRAME,keyTestHandler);
}
private static function keyUpHandler(e:KeyboardEvent):void {
delete keyObj[e.keyCode];
keyObjHasProperty()removeKeyTestHandler():null;
}
private static function keyObjHasProperty():Boolean {
for each (var j:Boolean in keyObj) {
if (j) {
return false;
}
}
return true;
}
private static function removeKeyTestHandler():void {
io.removeEventListener(Event.ENTER_FRAME,keyTestHandler);
}
public static function get KeyObj():Object {
return Key.keyObj;
}
}
}
使用:
import CYPL.Game.Key;
var box:Sprite;
with (box=Sprite(addChild(new Sprite))) {
graphics.beginFill(0xff0000);
graphics.drawRect(100,100,100,100);
}
Key.init(stage,keyTestHandler);
function keyTestHandler(e:Event) {
if (Key.isDown(Keyboard.LEFT)) {
box.x-=5;
}
if (Key.isDown(Keyboard.RIGHT)) {
box.x+=5;
}
if (Key.isDown(Keyboard.DOWN)) {
box.y+=5;
}
if (Key.isDown(Keyboard.UP)) {
box.y-=5;
}
}