How to make Popup-menu on specific card in flutter? - flutter

Question

This is my first time asking a question here. I'm a newbie in flutter and trying to create this popup menu (Screenshot) to select the quantity, of a specific product.
I tried the method below (Put Image and Container in a Stack and set visibility to false, and onTap set visibility true). But when I drag or Tap anywhere else it didn't hide.
Stack(
children: [
Column(
children: [
Image.network(
MyStrings.imgs[i],
height: 100,
),
],
),
Align(
alignment: Alignment.topRight,
child: InkWell(
onTap: () {
setState(() {
flag = true;
if (MyStrings.quantity[i] == 0) {
MyStrings.quantity[i] = 1;
}
});
},
child: Row(
children: [
Visibility(
visible: flag,
child: Container(
width: 25,
child: Center(
child: Expanded(
child: IconButton(
onPressed: () {
setState(() {
if (MyStrings.quantity[i] > 1)
MyStrings.quantity[i]--;
else {
setState(() {
MyStrings.quantity[i]--;
flag = false;
});
}
});
},
icon: Icon(Icons.remove, color: Colors.green),
),
),
),
),
),
Container(
width: 40,
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(50),
color: Colors.green,
),
child: Center(
child: Text(
MyStrings.quantity[i].toString(),
style: TextStyle(
color: Colors.green,
),
),
),
),
Visibility(
visible: flag,
child: Container(
width: 25,
child: Center(
child: Expanded(
child: IconButton(
onPressed: () {
setState(() {
MyStrings.quantity[i]++;
});
},
icon: Icon(
Icons.add,
color: Colors.green,
),
),
),
),
),
),
],
),
),
),
],
)
Code here is too messy as I am unable to explain much that's Why I attached a Screenshot with it.