I have void func:
//change state in select
void _onChangeSelect(Color? newValue) {
setState(() {
_selectedValue = newValue!;
});
}
How can I check for null without "!", but with "??".
CodePudding user response:
you need to provide a fallback then, a color to use when it is null. for example
//change state in select
void _onChangeSelect(Color? newValue) {
setState(() {
_selectedValue = newValue ?? Colors.white;
});
}
or if you want to keep the old value
//change state in select
void _onChangeSelect(Color? newValue) {
setState(() {
_selectedValue = newValue ?? _selectedValue ;
});
}
or simply write this
//change state in select
void _onChangeSelect(Color? newValue) {
setState(() {
if (newValue != null) {
_selectedValue = newValue;
}
});
}