ENTER_FRAME事件简单控制往返运动

 这个和as2基本一样，简单就写个控制ball_mc的往返运动效果：

 

 var ball_mc:Sprite=new Sprite();ball_mc.graphics.beginFill(0xff0000);ball_mc.graphics.drawCircle(10,10,10);ball_mc.graphics.endFill();addChild(ball_mc);ball_mc.x=50;ball_mc.y=50;var speed:int=5;ball_mc.addEventListener(Event.ENTER_FRAME,mymove);function mymove(event:Event){ball_mc.x+=speed;if(ball_mc.x>stage.stageWidth-ball_mc.width){speed=-speed;}else if(ball_mc.x<0){speed=-speed;}}