我试图改变小部件类型一会儿，它不工作，我不能解决这个问题。我的假设是，当我点击小部件它应该是可拖动的，它应该是拖动目标，而我不点击。

Row(
    mainAxisAlignment: MainAxisAlignment.center,
    children: [
        GestureDetector(
            dragStartBehavior: DragStartBehavior.start,
            onVerticalDragStart: (d) {
                c.index.value = 1;
            },
            onVerticalDragUpdate: (d) {
                c.index.value = 1;
            },
            onVerticalDragEnd: (d) {
                c.index.value = 0;
            },
            child: Obx(
                () => IndexedStack(
                index: c.index.value,
                children: [
                    DragTarget(
                        onAccept: (data) {
                            print(data);
                        },
                        builder: (context, candidateData, rejectedData) =>
                        Container(
                            width: 40,
                            height: 40,
                            color: Colors.grey,
                        )
                    ),
                    Draggable(
                        data: "data",
                        childWhenDragging: Container(
                            width: 40,
                            height: 40,
                            color: Colors.white,
                        ),
                        child: Container(
                            width: 40,
                            height: 40,
                            color: Colors.amber,
                        ),
                        feedback: Container(
                            width: 40,
                            height: 40,
                            color: Colors.blue,
                        )
                    ),
                ],
            ),
        ))
    ],
)