flutter: onTap Button listenable not work on position in stack

Question

I Trying to create a custom dialog. In dialog Close button is above of container:

Now I am trying to close dialog when user Tapped on this close icon:

  Widget build(BuildContext context) {
    return Dialog(
      insetPadding: EdgeInsets.symmetric(vertical: 0.0, horizontal: 30.0),
      child: Container(
        width: 300,
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Stack(
              overflow: Overflow.visible,
              children: [
                Visibility(
                  visible: true,
                  child: Positioned(
                    top: -15,
                    left: 0,
                    child: GestureDetector(
                        onTap: () {
                          print("Clicked");
                        },
                        child: CircleWidget()),
                  ),
                ),
                SingleChildScrollView(
                  child: Column(

But onTap not triggered ! I think it's lay down under some widget!!!

If GestureDetector be parent of Positioned on widget shape is messed.like this:

Although onTap not work like above .What is your idea?

Answer 1

As I guess before, a widget covered GestureDetector so I changed the position of This code :

Visibility(
  visible: widget.showCloseButton(),
  child: Positioned(
    top: -15,
    left: 0,

with :

SingleChildScrollView(
  child: Column(
    mainAxisSize: MainAxisSize.min,

Now GestureDetector works like a charm :-)

complete code:

  Widget build(BuildContext context) {
    return Dialog(
      insetPadding: EdgeInsets.symmetric(vertical: 0.0, horizontal: 30.0),
      child: Container(
        width: 300,
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Stack(
              overflow: Overflow.visible,
              children: [
                SingleChildScrollView(
                  child: Column(.....

                Visibility(
                  visible: true,
                  child: Positioned(
                    top: -15,
                    left: 0,
                    child: GestureDetector(
                        onTap: () {
                          print("Clicked");
                        },
                        child: CircleWidget()),
                  ),
                ),