onLongPress property Null safety

1. baguette
2. CalendarMarkerWidget
3. CalendarMarkerWidget
4. onLongPress property

CalendarMarkerWidget class

1. Constructors
2. CalendarMarkerWidget
3. Properties
4. color
5. hashCode
6. index
7. key
8. marker
9. onLongPress
10. onPress
11. rect
12. runtimeType
13. textColor
14. Methods
15. createElement
16. createState
17. debugDescribeChildren
18. debugFillProperties
19. noSuchMethod
20. toDiagnosticsNode
21. toString
22. toStringDeep
23. toStringShallow
24. toStringShort
25. Operators
26. operator ==
27. Constants
28. INDEX_CENTER
29. INDEX_FULL
30. INDEX_LEAD
31. INDEX_TRAIL