在闪存中设置边界

Question

我想用as3在闪存中设置我的影片剪辑边界，以便影片剪辑无法移出舞台。我怎样才能做到这一点？这是我现在的代码。我现在可以如何设定边界？

bij_mc.links_mc.play(); 
bij_mc.rechts_mc.play(); 

stage.addEventListener(KeyboardEvent.KEY_DOWN,beweeg); 
stage.addEventListener(KeyboardEvent.KEY_UP,stopbeweeg); 

function beweeg(evt:KeyboardEvent):void { 
    if (evt.keyCode==Keyboard.LEFT) { 
     bij_mc.links_mc.x -=10; 
     bij_mc.rechts_mc.x -=10; 
     bij_mc.lichaam_mc.x -=10; 
     bij_mc.links_mc.stop(); 
     bij_mc.rechts_mc.play(); 
     bij_mc.rotation = -5; 
    } else if (evt.keyCode==Keyboard.RIGHT) { 
     bij_mc.links_mc.x +=10; 
     bij_mc.rechts_mc.x +=10; 
     bij_mc.lichaam_mc.x += 10; 
     bij_mc.links_mc.play(); 
     bij_mc.rechts_mc.stop(); 
     bij_mc.rotation = 5; 
    } else if (evt.keyCode==Keyboard.UP) { 
     bij_mc.links_mc.y -=10; 
     bij_mc.rechts_mc.y -= 10; 
     bij_mc.lichaam_mc.y -= 10; 
     bij_mc.links_mc.play(); 
     bij_mc.rechts_mc.play(); 
     bij_mc.rotation = 0; 
    } else if (evt.keyCode==Keyboard.DOWN) { 
     bij_mc.links_mc.y +=10; 
     bij_mc.rechts_mc.y += 10; 
     bij_mc.lichaam_mc.y += 10; 
     bij_mc.links_mc.stop(); 
     bij_mc.rechts_mc.stop(); 
     bij_mc.rotation = 0; 
    } 
} 

function stopbeweeg(evt:KeyboardEvent):void { 
    bij_mc.links_mc.play(); 
    bij_mc.rechts_mc.play(); 
    bij_mc.rotation = 0; 
} 

Answer 1

stage.addEventListener(Event.ENTER_FRAME, onEnterFrame); 
private function onEnterFrame(event:Event):void 
{ 
    // update beweeg 
    checkBoundaries() 
} 

private function checkBoundaries():void 
{ 
    // left 
    if (bij_mc.x < 0) 
      bij_mc.x = 0; 
    // right 
    else if (bij_mc.x > stage.stageWidth) 
      bij_mc.x = stage.stageWidth - bij_mc.width; 
    // top 
    if (bij_mc.y < 0) 
      bij_mc.y = 0; 
    // bottom 
    else if (bij_mc.y > stage.stageHeight) 
      bij_mc.y = stage.stageHeight - bij_mc.height; 
} 

更新每个影片剪辑相应。