Dart APIunself_componentUnCardisExpandable isExpandable property Null safety bool isExpandable final Implementation final bool isExpandable; unself_component unself_component UnCard isExpandable property UnCard class Constructors UnCard Properties body footer hashCode header isExpandable isSelected key onTap runtimeType Methods build createElement debugDescribeChildren debugFillProperties noSuchMethod toDiagnosticsNode toString toStringDeep toStringShallow toStringShort Operators operator ==