Fix animation stopping when to fast

Author: letsar

lib/src/action_pane.dart

@@ -120,9 +120,9 @@ class _ActionPaneState extends State<ActionPane> implements RatioConfigurator {
     if (widget.dismissible != null) {
       controller!.animation.addListener(handleRatioChanged);
     }
-    controller!.actionPaneConfigurator = this;
     showMotion = true;
     updateThresholds();
+    controller!.actionPaneConfigurator = this;
   }
 
   void updateThresholds() {
@@ -167,6 +167,7 @@ class _ActionPaneState extends State<ActionPane> implements RatioConfigurator {
     return absoluteRatio;
   }
 
+  @override
   void handleEndGestureChanged() {
     final gesture = controller!.endGesture.value;
     final position = controller!.animation.value;
@@ -181,7 +182,6 @@ class _ActionPaneState extends State<ActionPane> implements RatioConfigurator {
             ((gesture.opening && position >= openThreshold) ||
                 gesture.closing && position > closeThreshold)) {
       controller!.openCurrentActionPane();
-
       return;
     }
 

lib/src/controller.dart

@@ -22,6 +22,9 @@ abstract class RatioConfigurator {
 
   /// The total extent ratio of this configurator.
   double get extentRatio;
+
+  /// A method to call when the end gesture changed.
+  void handleEndGestureChanged();
 }
 
 /// The direction of a gesture in the context of [Slidable].
@@ -132,7 +135,19 @@ class SlidableController {
   }
 
   /// The current action pane configurator.
-  RatioConfigurator? actionPaneConfigurator;
+  RatioConfigurator? get actionPaneConfigurator => _actionPaneConfigurator;
+  RatioConfigurator? _actionPaneConfigurator;
+  set actionPaneConfigurator(RatioConfigurator? value) {
+    if (_actionPaneConfigurator != value) {
+      _actionPaneConfigurator = value;
+      if (_replayEndGesture && value != null) {
+        _replayEndGesture = false;
+        value.handleEndGestureChanged();
+      }
+    }
+  }
+
+  bool _replayEndGesture = false;
 
   /// The value of the ratio over time.
   Animation<double> get animation => _animationController.view;
@@ -194,6 +209,12 @@ class SlidableController {
     } else {
       endGesture.value = ClosingGesture(velocity.abs());
     }
+
+    // If the movement is too fast, the actionPaneConfigurator may still be
+    // null. So we have to replay the end gesture when it will not be null.
+    if (actionPaneConfigurator == null) {
+      _replayEndGesture = true;
+    }
   }
 
   /// Closes the [Slidable].

test/action_pane_motions_test.dart

@@ -127,17 +127,15 @@ Future<void> testMotion({
     ),
   );
 
-  await tester.drag(findSlidable, drag);
-  await tester.pumpAndSettle();
+  await tester.dragAndHold(findSlidable, drag);
 
   double centerKey1 = centers[0];
   double centerKey2 = centers[1];
 
   expect(getCenter(findKey1), moreOrLessEquals(centerKey1));
   expect(getCenter(findKey2), moreOrLessEquals(centerKey2));
 
-  await tester.drag(findSlidable, drag);
-  await tester.pumpAndSettle();
+  await tester.dragAndHold(findSlidable, drag);
 
   centerKey1 = 12.5;
   centerKey2 = 62.5;
@@ -150,3 +148,11 @@ Future<void> testMotion({
   expect(getCenter(findKey1), moreOrLessEquals(centerKey1));
   expect(getCenter(findKey2), moreOrLessEquals(centerKey2));
 }
+
+extension on WidgetTester {
+  Future<void> dragAndHold(Finder finder, Offset offset) async {
+    final gesture = await startGesture(getCenter(finder));
+    await gesture.moveBy(offset);
+    await pump();
+  }
+}