flutter checkbox doesn't work - dart

Question

I want to build a checkbox with CheckboxListTile inside this widget dialog but when I tap the checkbox the checked on the checkbox doesn't change.
This is my code:
Future<Null> _showGroupDialog(BuildContext context) async {
await showDialog(
context: context,
builder: (BuildContext dialogContext) =>
Dialog(child: _buildCheckboxGroups(context)));
}
Widget _buildCheckboxGroups(BuildContext context) {
List<Widget> childrens = List.generate(_groups.length, (index) {
return CheckboxListTile(
title: Text(_groups[index].name),
value: _groups[index].checked,
onChanged: (bool val) {
setState(() {
_groups[index].checked = val;
});
},
);
});
return Container(
child: Column(
mainAxisSize: MainAxisSize.min,
crossAxisAlignment: CrossAxisAlignment.stretch,
children: childrens,
));
}
Btw, the onChange method is invoked when I tap the checkbox. Can anyone solve this?

Answer 1

class _MyHomePageState extends State<MyHomePage>{
//<Here you have to set default value for _groups[index].checked to false/true>
#override
Widget _buildCheckboxGroups(BuildContext context) {
List<Widget> childrens = List.generate(_groups.length, (index) {
return CheckboxListTile(
title: Text(_groups[index].name),
value: _groups[index].checked,
onChanged: (bool val) {
setState(() {
_groups[index].checked = val;
});
},
);
});}
Working Example is given below
class _MyHomePageState extends State<MyHomePage> {
bool flagWarranty=false;
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text(widget.title)),
body: new Container(
padding: new EdgeInsets.all(20.0),
child: new Form(
key: this._formKey,
child: new ListView(
children: <Widget>[
new Checkbox(
value: flagWarranty,
onChanged: (bool value) {
setState((
) {
flagWarranty=value;
});
},
)
],),)));
}}