Flutter > Unselect a RadioButton in a View.builder - flutter

Question

I am not finding any answer for my question so I am hoping to find someone who can help.
I have a GridView with text buttons.
I can select the buttons, however I can't unselect any of them.
this is my code
#override
Widget build(BuildContext context) {
return TextButton(
onLongPress: () => showDialog<String>(
),
style: ButtonStyle(
side: MaterialStateProperty.all(BorderSide(
width: 5,
color: widget.isSelected ? Colors.black : Colors.white)),
shape: MaterialStateProperty.all(
RoundedRectangleBorder(borderRadius: BorderRadius.circular(10))),
backgroundColor: MaterialStateProperty.all(widget.pickerColor),
elevation: MaterialStateProperty.all(10)),
onPressed: () {
widget.selectedCard(widget.index); //This selects the cards, how to unselect (if Statements?)
},
child: FittedBox(
fit: BoxFit.fitHeight,
child: Text(
widget.cardTitle,
style: TextStyle(
fontSize: 17,
color: useWhiteForeground(widget.pickerColor)
? const Color(0xffffffff)
: const Color(0xff000000),
),
),
),
);
}
}
This is the Grid
#override
Widget build(BuildContext context) {
return Consumer<MyCardData>(
builder: (context, cardData, child) {
return Padding(
padding: const EdgeInsets.all(10),
child: GridView.builder(
clipBehavior: Clip.none,
itemBuilder: (context, index) {
final card = cardData.cards[index];
return MyCard(
selectedCard,
index: index,
isSelected: _selectedCard == index,
cardTitle: card.name,
pickerColor: card.cardColor,
deleteCallback: () {
cardData.deleteCallback(card);
},
);
},
itemCount: cardData.cardCount,
gridDelegate: const SliverGridDelegateWithMaxCrossAxisExtent(
maxCrossAxisExtent: 150,
childAspectRatio: 2.5 / 1,
crossAxisSpacing: 0,
mainAxisSpacing: 0,
),
),
);
},
);
}
}
feel free to use my git to see the full code
get from version control

Answer 1

since you want to make a single selection, it will need a simple workaround.
int _selectedCard = -1;
selectedCard(index) {
// this condition is when user press the same button
// set the _selectedCard back into -1
if (_selectedCard == index) {
setState(() {
_selectedCard = -1;
});
} else{
setState(() {
_selectedCard = index;
});
}
}