add method

  1. @override
bool add(
  1. E element
)
override

Adds value to the set.

Returns true if value (or an equal value) was not yet in the set. Otherwise returns false and the set is not changed.

Example:

final dateTimes = <DateTime>{};
final time1 = DateTime.fromMillisecondsSinceEpoch(0);
final time2 = DateTime.fromMillisecondsSinceEpoch(0);
// time1 and time2 are equal, but not identical.
assert(time1 == time2);
assert(!identical(time1, time2));
final time1Added = dateTimes.add(time1);
print(time1Added); // true
// A value equal to time2 exists already in the set, and the call to
// add doesn't change the set.
final time2Added = dateTimes.add(time2);
print(time2Added); // false

print(dateTimes); // {1970-01-01 02:00:00.000}
assert(dateTimes.length == 1);
assert(identical(time1, dateTimes.first));
print(dateTimes.length);

Implementation

@override
bool add(E element) {
  bool result = _values.add(element);

  if (result) {
    // Listen to the element if asked to and if it is possible
    if (_propagateNotification &&
        element != null &&
        element is ChangeNotifier) {
      element.addListener(_propagate);
    }

    notifyListeners();
  }

  return result;
}