fixed onSubmitted behavior and public State classes (ubuntu-flutter-community#86)

* call onSubmitted when losing focus

* make State classes public

* bugfix: fixup wasn't called when onSubmitted was null

---------

Co-authored-by: md <[email protected]>
Co-authored-by: ws <[email protected]>

Author: 3 people

lib/src/base_spin_box.dart

@@ -164,7 +164,8 @@ mixin SpinBoxMixin<T extends BaseSpinBox> on State<T> {
       if (hasFocus) {
         _selectAll();
       } else {
-        fixupValue(_controller.text);
+        final value = fixupValue(_controller.text);
+        widget.onSubmitted?.call(value);
       }
     });
   }

lib/src/cupertino/spin_box.dart

@@ -265,10 +265,10 @@ class CupertinoSpinBox extends BaseSpinBox {
   final void Function(double)? onSubmitted;
 
   @override
-  State<CupertinoSpinBox> createState() => _CupertinoSpinBoxState();
+  State<CupertinoSpinBox> createState() => CupertinoSpinBoxState();
 }
 
-class _CupertinoSpinBoxState extends State<CupertinoSpinBox> with SpinBoxMixin {
+class CupertinoSpinBoxState extends State<CupertinoSpinBox> with SpinBoxMixin {
   @override
   Widget build(BuildContext context) {
     final isHorizontal = widget.direction == Axis.horizontal;

lib/src/material/spin_box.dart

@@ -273,10 +273,10 @@ class SpinBox extends BaseSpinBox {
   final void Function(double)? onSubmitted;
 
   @override
-  State<SpinBox> createState() => _SpinBoxState();
+  State<SpinBox> createState() => SpinBoxState();
 }
 
-class _SpinBoxState extends State<SpinBox> with SpinBoxMixin {
+class SpinBoxState extends State<SpinBox> with SpinBoxMixin {
   Color? _iconColor(ThemeData theme, String? errorText) {
     if (!widget.enabled) return theme.disabledColor;
     if (hasFocus && errorText == null) return theme.colorScheme.primary;