Animate a CupertinoButton based on tap move events only if the move happens between a tap down and a tap up (#165729)

Fixes flutter/flutter#165724

Author: jason-simmons

packages/flutter/lib/src/cupertino/button.dart

@@ -356,15 +356,18 @@ class _CupertinoButtonState extends State<CupertinoButton> with SingleTickerProv
   }
 
   bool _buttonHeldDown = false;
+  bool _tapInProgress = false;
 
   void _handleTapDown(TapDownDetails event) {
+    _tapInProgress = true;
     if (!_buttonHeldDown) {
       _buttonHeldDown = true;
       _animate();
     }
   }
 
   void _handleTapUp(TapUpDetails event) {
+    _tapInProgress = false;
     if (_buttonHeldDown) {
       _buttonHeldDown = false;
       _animate();
@@ -377,19 +380,20 @@ class _CupertinoButtonState extends State<CupertinoButton> with SingleTickerProv
   }
 
   void _handleTapCancel() {
+    _tapInProgress = false;
     if (_buttonHeldDown) {
       _buttonHeldDown = false;
       _animate();
     }
   }
 
-  void _handTapMove(TapMoveDetails event) {
+  void _handleTapMove(TapMoveDetails event) {
     final RenderBox renderObject = context.findRenderObject()! as RenderBox;
     final Offset localPosition = renderObject.globalToLocal(event.globalPosition);
     final bool buttonShouldHeldDown = renderObject.paintBounds
         .inflate(CupertinoButton.tapMoveSlop())
         .contains(localPosition);
-    if (buttonShouldHeldDown != _buttonHeldDown) {
+    if (_tapInProgress && buttonShouldHeldDown != _buttonHeldDown) {
       _buttonHeldDown = buttonShouldHeldDown;
       _animate();
     }
@@ -512,7 +516,7 @@ class _CupertinoButtonState extends State<CupertinoButton> with SingleTickerProv
                 instance.onTapDown = enabled ? _handleTapDown : null;
                 instance.onTapUp = enabled ? _handleTapUp : null;
                 instance.onTapCancel = enabled ? _handleTapCancel : null;
-                instance.onTapMove = enabled ? _handTapMove : null;
+                instance.onTapMove = enabled ? _handleTapMove : null;
                 instance.gestureSettings = gestureSettings;
               },
             ),

packages/flutter/test/cupertino/button_test.dart

@@ -912,6 +912,30 @@ void main() {
     expect(opacity.opacity.value, 0.4);
   }, variant: TargetPlatformVariant.all());
 
+  testWidgets('Drag outside button within ListView does not leave the button pressed', (
+    WidgetTester tester,
+  ) async {
+    await tester.pumpWidget(
+      boilerplate(
+        child: ListView(
+          children: <Widget>[CupertinoButton(onPressed: () {}, child: const Text('Tap me'))],
+        ),
+      ),
+    );
+    final FadeTransition opacity = tester.widget(
+      find.descendant(of: find.byType(CupertinoButton), matching: find.byType(FadeTransition)),
+    );
+
+    final TestGesture gesture = await tester.createGesture();
+    addTearDown(gesture.removePointer);
+
+    await gesture.down(tester.getTopLeft(find.byType(CupertinoButton)));
+    await gesture.moveBy(const Offset(1, 1));
+    await gesture.moveBy(Offset(0, -CupertinoButton.tapMoveSlop() - 5));
+    await tester.pumpAndSettle();
+    expect(opacity.opacity.value, 1.0);
+  });
+
   testWidgets('onPressed trigger takes into account MoveSlop.', (WidgetTester tester) async {
     bool value = false;
     await tester.pumpWidget(