flutter showMenu

GestureDetector(
onLongPressDown: (details) {
setState(() {
dx = details.globalPosition.dx;
dy = details.globalPosition.dy;
});
},
onLongPress: () {
showMenu(
context: context,

      ///这个坐标值不好调整，下面我的经验值，位置在手指点击点的左下方，想往左移动给110+数字 往下移动180加数字
      position: RelativeRect.fromLTRB(dx, dy, dx + 110, dy - 40),
      items: [
        ///建议指定value属性
        PopupMenuItem<String>(
          value: 'one',
          onTap: () => debugPrint('tap one'),
          child: const Text('删除'),
        ),
        PopupMenuItem<String>(
          value: 'two',
          onTap: () => debugPrint('tap two'),
          child: const Text('管理列表'),
        ),
      ],
    );
  },

child: Text（“你好”),
);