为什么 startDrag() 和 stopDrag() 不影响 x,y 坐标？

Question

当我使用 startDrag() 和 stopDrag() 拖动对象时，为什么它不影响对象的 x,y 坐标？

你可以运行这个例子并亲自看看 （移动圆圈并查看跟踪消息）：

<fx:Script>
    <![CDATA[
        import mx.events.FlexEvent;

        private function mouseDown(event:MouseEvent):void {
            circle.startDrag(false, new Rectangle(0,0 , 400, 400));
        }


        private function mouseReleased(event:MouseEvent):void {
            circle.stopDrag();
            trace("ended drag X: " + circle.x + ", Y: " + circle.y);
        }


        protected function application1_creationCompleteHandler(event:FlexEvent):void
        {
            circle.addEventListener(MouseEvent.MOUSE_DOWN, mouseDown) 
            circle.addEventListener(MouseEvent.MOUSE_UP, mouseReleased);
        }

    ]]>
</fx:Script>

<fx:Declarations>
    <!-- Place non-visual elements (e.g., services, value objects) here -->
</fx:Declarations>

<s:Rect id="target1" x="0" y="10" width="150" height="150">
    <s:fill>
        <s:SolidColor color="0xFF0000"/>
    </s:fill>
</s:Rect>

<s:Rect id="target2" x="200" y="10" width="150" height="150">
    <s:fill>
        <s:SolidColor color="0x00FF00"/>
    </s:fill>
</s:Rect>

<s:Graphic id="circle" x="200" y="200">
    <s:Ellipse height="100" width="250">
        <s:stroke>
            <s:SolidColorStroke color="0x000000" weight="2"/>
        </s:stroke>
        <s:fill>
            <s:RadialGradient>
                <s:entries>
                    <s:GradientEntry color="0x0056FF" ratio="0.00" alpha="0.5"/>
                    <s:GradientEntry color="0x00CC99" ratio="0.33" alpha="0.5"/>
                    <s:GradientEntry color="0xECEC21" ratio="0.66" alpha="0.5"/>
                </s:entries>
            </s:RadialGradient>
        </s:fill>
    </s:Ellipse>
</s:Graphic>

Answer 1

试试这个代码：

    import mx.core.mx_internal;
    use namespace mx_internal;

    private function mouseDown(event:MouseEvent):void {
        circle.startDrag(false, new Rectangle(0,0 , 400, 400));
    }


    private function mouseReleased(event:MouseEvent):void {
        circle.stopDrag();

        circle.x = circle.mx_internal::$x;
        circle.y = circle.mx_internal::$y;

        trace("ended drag X: " + circle.x + ", Y: " + circle.y);
    }


    protected function application1_creationCompleteHandler(event:FlexEvent):void
    {
        circle.addEventListener(MouseEvent.MOUSE_DOWN, mouseDown) 
        circle.addEventListener(MouseEvent.MOUSE_UP, mouseReleased);
    }

]]>

Answer 2

主要的巨魔，但是：circle.getBounds() 是一个更好的解决方案，不需要额外的工作。

Answer 3

我认为问题在于数据仅在调用函数时传递。更简单地说，您要检查的信息没有更新。所以你可能想尝试以下操作：

circle.addEventListener(MouseEvent.MOUSE_DOWN, mouseDown);
circle.addEventListener(MouseEvent.MOUSE_UP, mouseReleased);

private function mouseDown(event:MouseEvent):void {
    addEventListener(Event.ENTER_FRAME, dragMe);
}
function dragMe (e:Event) {
    circle.startDrag(false, new Rectangle(0,0 , 400, 400));
    trace("starting drag X: " + circle.x + ", Y: " + circle.y);
}
private function mouseReleased(event:MouseEvent):void {
    circle.stopDrag();
    trace("ended drag X: " + circle.x + ", Y: " + circle.y);
}

像这样的事情。使用 ENTER_FRAME 事件使 Flash 每帧更新并传递数据。因此默认情况下，该频率为每秒 24 次。 （但这意味着 Flash 每秒也会跟踪 24 次）。我认为没有必要对 mouseReleased 函数执行此操作，因为该位置只需要检查一次。