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How to add active dates in the Flutter Calendar
2 mins read
In the Flutter Event Calendar, you can add active dates by using the reverse concept of the blackoutDates.
STEP 1: In initState(), set the default values for event calendar.
List<DateTime>? _blackoutDateCollection= <DateTime>[];
List<DateTime>? _activeDates;
@override
void initState() {
DateTime today = DateTime.now();
today = DateTime(today.year, today.month, today.day);
_activeDates = [
today,
today.add(Duration(days: 5)),
today.add(Duration(days: 10)),
today.add(Duration(days: 15)),
today.add(Duration(days: 20)),
today.add(Duration(days: 25)),
today.add(Duration(days: 30)),
today.add(Duration(days: 35))
];
super.initState();
}
STEP 2: Use onViewChanged callback to check the mentioned active dates are equal to the visible dates. If they match, then those dates can be selected. Otherwise, add the remaining dates to the blackout dates collection.
void viewChanged(ViewChangedDetails viewChangedDetails) {
DateTime date;
DateTime startDate = viewChangedDetails.visibleDates[0];
DateTime endDate = viewChangedDetails
.visibleDates[viewChangedDetails.visibleDates.length - 1];
List<DateTime> _blackDates = <DateTime>[];
for (date = startDate;
date.isBefore(endDate) || date == endDate;
date = date.add(const Duration(days: 1))) {
if (_activeDates!.contains(date)) {
continue;
}
_blackDates.add(date);
}
SchedulerBinding.instance!.addPostFrameCallback((timeStamp) {
setState(() {
_blackoutDateCollection = _blackDates;
});
});
}
STEP 3: Assign the above date collections to the blackoutDates property of the Flutter event calendar.
child: SfCalendar( view: CalendarView.month, blackoutDates: _blackoutDateCollection, blackoutDatesTextStyle: TextStyle( color: Colors.grey, decoration: TextDecoration.lineThrough), onViewChanged: viewChanged, ),
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