Call onSubmitted when step buttons are pressed (ubuntu-flutter-community#81)

Author: BenGMiles

lib/src/base_spin_box.dart

@@ -37,6 +37,7 @@ abstract class BaseSpinBox extends StatefulWidget {
   double get value;
   int get decimals;
   int get digits;
+  void Function(double)? get onSubmitted;
   ValueChanged<double>? get onChanged;
   bool Function(double value)? get canChange;
   VoidCallback? get beforeChange;
@@ -127,6 +128,7 @@ mixin SpinBoxMixin<T extends BaseSpinBox> on State<T> {
 
     widget.beforeChange?.call();
     setState(() => _updateController(value, newValue));
+    widget.onSubmitted?.call(double.parse(_formatText(newValue)));
     widget.afterChange?.call();
   }
 

lib/src/cupertino/spin_box.dart

@@ -256,7 +256,12 @@ class CupertinoSpinBox extends BaseSpinBox {
   /// See [CupertinoTextField.toolbarOptions].
   final ToolbarOptions? toolbarOptions;
 
-  /// See [CupertinoTextField.onSubmitted]. Is called with a formatted value.
+  /// See [TextField.onSubmitted].
+  ///
+  /// Is also called when an increment or decrement button is pressed.
+  ///
+  /// Value is formatted.
+  @override
   final void Function(double)? onSubmitted;
 
   @override

lib/src/material/spin_box.dart

@@ -264,7 +264,12 @@ class SpinBox extends BaseSpinBox {
   /// See [TextField.toolbarOptions].
   final ToolbarOptions? toolbarOptions;
 
-  /// See [TextField.onSubmitted]. Is called with a formatted value.
+  /// See [TextField.onSubmitted].
+  ///
+  /// Is also called when an increment or decrement button is pressed.
+  ///
+  /// Value is formatted.
+  @override
   final void Function(double)? onSubmitted;
 
   @override