Flash CS５ 多次添加同一个显示对象例子

同一个显示对象不论被代码加入显示列表多少次，在屏幕上只会有一个显示对象。

例：文档类SampleAdd中生成一个星星显示对象star，两个容器conA和conB。ConA坐标没有位置，默认是(0,0),在屏幕左上方；ConB横坐标设为200，即向右移动了200像素，在(200,0)。star的纵坐标设为100，表示它相对于父容器的坐标原点往下移100像素。

   同时还生成了3个Sprite当按钮用，分别标记为A,B,X。单击A，则在容器中添加入星星；单击B，则在容器B 中加入星星，但是，不论我们点多少次，屏蔽上只会有一个星星，不会点多少就加多少星星。单击X，则把对象从显示列表中移除。

SampleAdd .cs(文档类)

package { import flash.display.Sprite; import flash.events.MouseEvent; public class SampleAdd extends Sprite {  private var conA:Sprite;  private var conB:Sprite;  private var buttonA:RectSprite;  private var buttonB:RectSprite;  private var buttonX:RectSprite;  private var star:StartShape;  public function SampleAdd()  {   star=new StartShape();   star.y = 100;   conA=new Sprite();   conB=new Sprite();   conB.x = 200;   addChild(conA);   addChild(conB);   buttonA = new RectSprite("A",0xff9900);   buttonB = new RectSprite("B",0x669900);   buttonX = new RectSprite("X",0x669900);   buttonA.y = 100;   buttonB.x = 150;   buttonB.y = 100;   buttonX.y = 160;   buttonX.x = 50;   addChild(buttonA);   addChild(buttonB);   addChild(buttonX);   buttonA.addEventListener(MouseEvent.CLICK,addStarInContainer);   buttonB.addEventListener(MouseEvent.CLICK,addStarInContainer);   buttonX.addEventListener(MouseEvent.CLICK,removeStar);   trace(this.contains(star));  }  private function addStarInContainer(evt:MouseEvent):void  {   if (evt.currentTarget == buttonA)   {    conA.addChild(star);    trace("容器A加入了星星");   }   else   {    conB.addChild(star);    trace("容器B加入了星星");   }  }  private function removeStar(evt:MouseEvent):void  {   if (conA.contains(star))   {    conA.removeChild(star);    trace("移除容器A的星星");   }   else if (conB.contains(star))   {    conB.removeChild(star);    trace("移除容器B的星星");   }   else   {    trace("星星已经不存在，不需要再移除");   }  } }}

RectSprite.cs

package  { import flash.text.TextField; import flash.display.Sprite;  public class RectSprite extends Sprite{  private var _lable:TextField    public function RectSprite(lableName:String,color:uint) {   this.graphics.lineStyle(2,0x85DB18);   this.graphics.beginFill(color);   this.graphics.drawRoundRect(0,0,100,50,10,10);   this.graphics.endFill();      _lable=new TextField();   _lable.htmlText="<font size='24'><b>"+ lableName +"</b></font>";   _lable.autoSize="left";   addChild(_lable);  } } }

StartShape .cs

package  {//import flash.display.Sprite;import flash.display.GradientType;import flash.display.Shape;public class StartShape extends Shape{public function StartShape(x:Number=0,y:Number=0,points:int=5,innerRadius:Number=20,outerRadius:Number=50,angle:Number=0,color:uint=0xff0000) {var count=Math.abs(points);this.graphics.lineStyle(2,0x85DB18);this.graphics.beginFill(color);if(count > 2){var step,halfStep,start,n,dx,dy;step=(Math.PI*2)/points;halfStep=step/2;start=(angle/180)*Math.PI;this.graphics.moveTo(x+(Math.cos(start)*outerRadius),  y-(Math.sin(start)*outerRadius));for(n=1; n <= count; n++){dx=x+Math.cos(start+(step*n)-halfStep)*innerRadius;dy=y-Math.sin(start+(step*n)-halfStep)*innerRadius;this.graphics.lineTo(dx,dy);dx=x+Math.cos(start+(step*n))*outerRadius;dy=y-Math.sin(start+(step*n))*outerRadius;this.graphics.lineTo(dx,dy);}}this.graphics.endFill();}}}

 效果