TextInputAction constructor Null safety

1. Flutter
2. services
3. TextInputAction
4. TextInputAction const constructor

TextInputAction enum

1. Constructors
2. TextInputAction
3. Values
4. none
5. unspecified
6. done
7. go
8. search
9. send
10. next
11. previous
12. continueAction
13. join
14. route
15. emergencyCall
16. newline
17. Properties
18. hashCode
19. index
20. runtimeType
21. Methods
22. noSuchMethod
23. toString
24. Operators
25. operator ==
26. Constants
27. values