Make page step nullable (#62)

lib/src/base_spin_box.dart

@@ -33,7 +33,7 @@ abstract class BaseSpinBox extends StatefulWidget {
   double get min;
   double get max;
   double get step;
-  double get pageStep;
+  double? get pageStep;
   double get value;
   int get decimals;
   int get digits;
@@ -69,8 +69,10 @@ mixin SpinBoxMixin<T extends BaseSpinBox> on State<T> {
       // https://github.com/flutter/flutter/issues/92717
       LogicalKeySet(LogicalKeyboardKey.arrowUp): _stepUp,
       LogicalKeySet(LogicalKeyboardKey.arrowDown): _stepDown,
-      LogicalKeySet(LogicalKeyboardKey.pageUp): _pageStepUp,
-      LogicalKeySet(LogicalKeyboardKey.pageDown): _pageStepDown,
+      if (widget.pageStep != null) ...{
+        LogicalKeySet(LogicalKeyboardKey.pageUp): _pageStepUp,
+        LogicalKeySet(LogicalKeyboardKey.pageDown): _pageStepDown,
+      }
     };
   }
 
@@ -98,8 +100,8 @@ mixin SpinBoxMixin<T extends BaseSpinBox> on State<T> {
   void _stepUp() => setValue(value + widget.step);
   void _stepDown() => setValue(value - widget.step);
 
-  void _pageStepUp() => setValue(value + widget.pageStep);
-  void _pageStepDown() => setValue(value - widget.pageStep);
+  void _pageStepUp() => setValue(value + widget.pageStep!);
+  void _pageStepDown() => setValue(value - widget.pageStep!);
 
   void _updateValue() {
     final v = _parseValue(_controller.text);

lib/src/cupertino/spin_box.dart

@@ -52,7 +52,7 @@ class CupertinoSpinBox extends BaseSpinBox {
     this.min = 0,
     this.max = 100,
     this.step = 1,
-    this.pageStep = 10,
+    this.pageStep,
     this.value = 0,
     this.interval = const Duration(milliseconds: 100),
     this.acceleration,
@@ -120,11 +120,11 @@ class CupertinoSpinBox extends BaseSpinBox {
   @override
   final double step;
 
-  /// The page step size for incrementing and decrementing the value.
+  /// An optional page step size for incrementing and decrementing the value.
   ///
-  /// Defaults to `10.0`.
+  /// Defaults to `null`.
   @override
-  final double pageStep;
+  final double? pageStep;
 
   /// The current value.
   ///

lib/src/material/spin_box.dart

@@ -53,7 +53,7 @@ class SpinBox extends BaseSpinBox {
     this.min = 0,
     this.max = 100,
     this.step = 1,
-    this.pageStep = 10,
+    this.pageStep,
     this.value = 0,
     this.interval = const Duration(milliseconds: 100),
     this.acceleration,
@@ -118,11 +118,11 @@ class SpinBox extends BaseSpinBox {
   @override
   final double step;
 
-  /// The page step size for incrementing and decrementing the value.
+  /// An optional page step size for incrementing and decrementing the value.
   ///
-  /// Defaults to `10.0`.
+  /// Defaults to `null`.
   @override
-  final double pageStep;
+  final double? pageStep;
 
   /// The current value.
   ///

test/cupertino_spinbox_test.dart

@@ -21,7 +21,13 @@ void main() {
   });
 
   testInput<CupertinoSpinBox>(() {
-    return TestApp(widget: CupertinoSpinBox(value: 1, autofocus: true));
+    return TestApp(
+      widget: CupertinoSpinBox(
+        value: 1,
+        autofocus: true,
+        pageStep: 10,
+      ),
+    );
   });
 
   testInput<CupertinoSpinBox>(() {
@@ -30,6 +36,7 @@ void main() {
         value: 1,
         autofocus: true,
         focusNode: FocusNode(),
+        pageStep: 10,
       ),
     );
   });

test/material_spinbox_test.dart

@@ -22,12 +22,17 @@ void main() {
   });
 
   testInput<SpinBox>(() {
-    return TestApp(widget: SpinBox(value: 1, autofocus: true));
+    return TestApp(widget: SpinBox(value: 1, autofocus: true, pageStep: 10));
   });
 
   testInput<SpinBox>(() {
     return TestApp(
-      widget: SpinBox(value: 1, autofocus: true, focusNode: FocusNode()),
+      widget: SpinBox(
+        value: 1,
+        autofocus: true,
+        focusNode: FocusNode(),
+        pageStep: 10,
+      ),
     );
   });