fix: prevent Android dismiss handoff jumps

.changeset/calm-cards-glide.md

@@ -0,0 +1,7 @@
+---
+'@react-native-motion-kit/swipe-deck': patch
+---
+
+Prevent gesture-driven dismisses from briefly jumping when the finger is released on Android.
+Committed swipes now animate only their primary dismiss axis, preserving the final cross-axis drag
+position instead of restarting an unnecessary timing animation during the gesture handoff.

src/__tests__/animation.test.ts

@@ -3,6 +3,7 @@ import { Easing } from 'react-native-reanimated';
 
 import {
   mergeSwipeDeckMotionPreset,
+  resolveSwipeDeckDismissAxisMotion,
   resolveSwipeDeckDismissAxisDuration,
   resolveSwipeDeckDismissDestination,
   resolveSwipeDeckDismissDestinationDistance,
@@ -14,6 +15,40 @@ import {
   SwipeDeckMotion,
 } from '../motion/animation';
 
+describe('resolveSwipeDeckDismissAxisMotion', () => {
+  it('selects only the dismiss axis and leaves cross-axis displacement out of the animation', () => {
+    expect(
+      resolveSwipeDeckDismissAxisMotion({
+        destination: { axis: 'x', translateX: 620, translateY: 37 },
+        translationX: 180,
+        translationY: 12,
+        velocityX: 900,
+        velocityY: 240,
+      }),
+    ).toEqual({
+      axis: 'x',
+      destination: 620,
+      translation: 180,
+      velocity: 900,
+    });
+
+    expect(
+      resolveSwipeDeckDismissAxisMotion({
+        destination: { axis: 'y', translateX: 37, translateY: -780 },
+        translationX: 12,
+        translationY: -180,
+        velocityX: 240,
+        velocityY: -900,
+      }),
+    ).toEqual({
+      axis: 'y',
+      destination: -780,
+      translation: -180,
+      velocity: -900,
+    });
+  });
+});
+
 describe('SwipeDeckMotion', () => {
   it('creates a discriminated tinder motion preset', () => {
     expect(SwipeDeckMotion.tinder({ nextScale: 0.9 })).toMatchObject({

src/hooks/useSwipeDeckGestureRuntime.ts

@@ -18,8 +18,9 @@ import type {
 import { resolveSwipeDirection } from '../core/directions';
 import { resolveSwipeProgressIntent, resolveSwipeDirectionSignal } from '../core/swipeDeckRuntime';
 import {
-  resolveSwipeDeckDismissDestination,
+  resolveSwipeDeckDismissAxisMotion,
   resolveSwipeDeckDismissAxisDuration,
+  resolveSwipeDeckDismissDestination,
   resolveSwipeDeckGestureStartYRatio,
 } from '../motion/animation';
 
@@ -244,10 +245,17 @@ export function useSwipeDeckGestureRuntime({
             translationX: event.translationX,
             translationY: event.translationY,
           });
+          const dismissAxisMotion = resolveSwipeDeckDismissAxisMotion({
+            destination,
+            translationX: event.translationX,
+            translationY: event.translationY,
+            velocityX: event.velocityX,
+            velocityY: event.velocityY,
+          });
           const resolvedDismissDuration = resolveSwipeDeckDismissAxisDuration({
-            translation: destination.axis === 'x' ? event.translationX : event.translationY,
-            velocity: destination.axis === 'x' ? event.velocityX : event.velocityY,
-            destination: destination.axis === 'x' ? destination.translateX : destination.translateY,
+            translation: dismissAxisMotion.translation,
+            velocity: dismissAxisMotion.velocity,
+            destination: dismissAxisMotion.destination,
             duration: dismissDuration,
             minDuration: dismissMinDuration,
             maxDuration: dismissMaxDuration,
@@ -262,22 +270,25 @@ export function useSwipeDeckGestureRuntime({
           swipeDirectionSignal.set(progressDirection);
           signedSwipeProgress.set(withTiming(progressDirection, dismissTimingConfig));
           swipeProgress.set(withTiming(1, dismissTimingConfig));
-          activeTranslateY.set(
-            withTiming(destination.translateY, dismissTimingConfig, (finished) => {
-              'worklet';
 
-              if (destination.axis === 'y') {
+          // Keep the cross axis on its last drag frame. Restarting it from the final Android
+          // gesture event can introduce a visible one-frame jump at the dismiss handoff.
+          if (dismissAxisMotion.axis === 'y') {
+            activeTranslateY.set(
+              withTiming(dismissAxisMotion.destination, dismissTimingConfig, (finished) => {
+                'worklet';
+
                 completeSwipeDismiss(finished, currentAttachmentGeneration, direction, 'gesture');
-              }
-            }),
-          );
+              }),
+            );
+            return;
+          }
+
           activeTranslateX.set(
-            withTiming(destination.translateX, dismissTimingConfig, (finished) => {
+            withTiming(dismissAxisMotion.destination, dismissTimingConfig, (finished) => {
               'worklet';
 
-              if (destination.axis === 'x') {
-                completeSwipeDismiss(finished, currentAttachmentGeneration, direction, 'gesture');
-              }
+              completeSwipeDismiss(finished, currentAttachmentGeneration, direction, 'gesture');
             }),
           );
         })

src/motion/animation.ts

@@ -78,6 +78,21 @@ export type SwipeDeckTranslation = SwipeDeckMotionTranslation;
 
 export type SwipeDeckDismissDestination = SwipeDeckMotionVector;
 
+type SwipeDeckDismissAxisMotion = {
+  axis: SwipeDeckDismissDestination['axis'];
+  translation: number;
+  velocity: number;
+  destination: number;
+};
+
+type ResolveSwipeDeckDismissAxisMotionArgs = {
+  destination: SwipeDeckDismissDestination;
+  translationX: number;
+  translationY: number;
+  velocityX: number;
+  velocityY: number;
+};
+
 type ResolveSwipeDeckTinderRotationAnchorArgs = {
   mode: SwipeDeckTinderRotationMode;
   origin?: SwipeDeckTinderFixedRotationOrigin;
@@ -339,6 +354,32 @@ export function resolveSwipeDeckDismissDestination(
   });
 }
 
+export function resolveSwipeDeckDismissAxisMotion({
+  destination,
+  translationX,
+  translationY,
+  velocityX,
+  velocityY,
+}: ResolveSwipeDeckDismissAxisMotionArgs): SwipeDeckDismissAxisMotion {
+  'worklet';
+
+  if (destination.axis === 'x') {
+    return {
+      axis: 'x',
+      translation: translationX,
+      velocity: velocityX,
+      destination: destination.translateX,
+    };
+  }
+
+  return {
+    axis: 'y',
+    translation: translationY,
+    velocity: velocityY,
+    destination: destination.translateY,
+  };
+}
+
 function mergeSwipeDeckTinderRotationConfig(
   base: SwipeDeckTinderRotationConfig | undefined,
   override: SwipeDeckTinderRotationConfig | undefined,