[General] Don't emit duplicate events for NativeViewGestureHandler

packages/react-native-gesture-handler/android/src/main/java/com/swmansion/gesturehandler/core/NativeViewGestureHandler.kt

@@ -31,6 +31,10 @@ class NativeViewGestureHandler : GestureHandler() {
 
   private var hook: NativeViewGestureHandlerHook = defaultHook
 
+  private data class ActiveUpdateSnapshot(val pointerInside: Boolean, val numberOfPointers: Int, val pointerType: Int)
+
+  private var lastActiveUpdate: ActiveUpdateSnapshot? = null
+
   init {
     shouldCancelWhenOutside = true
   }
@@ -163,6 +167,21 @@ class NativeViewGestureHandler : GestureHandler() {
 
   override fun onReset() {
     this.hook = defaultHook
+    lastActiveUpdate = null
+  }
+
+  override fun dispatchHandlerUpdate(event: MotionEvent) {
+    val snapshot = ActiveUpdateSnapshot(isWithinBounds, numberOfPointers, pointerType)
+    if (snapshot == lastActiveUpdate) {
+      return
+    }
+    lastActiveUpdate = snapshot
+    super.dispatchHandlerUpdate(event)
+  }
+
+  override fun dispatchStateChange(newState: Int, prevState: Int) {
+    lastActiveUpdate = null
+    super.dispatchStateChange(newState, prevState)
   }
 
   override fun wantsToAttachDirectlyToView() = true

packages/react-native-gesture-handler/apple/Handlers/RNNativeViewHandler.mm

@@ -113,6 +113,7 @@ - (void)updateStateIfScrollView
 @implementation RNNativeViewGestureHandler {
   BOOL _shouldActivateOnStart;
   BOOL _disallowInterruption;
+  RNGestureHandlerEventExtraData *_lastActiveExtraData;
 }
 
 - (instancetype)initWithTag:(NSNumber *)tag
@@ -180,6 +181,16 @@ - (void)unbindFromView
   [super unbindFromView];
 }
 
+- (void)sendActiveStateEventIfChangedForView:(UIView *)sender extraData:(RNGestureHandlerEventExtraData *)extraData
+{
+  if ([_lastActiveExtraData.data isEqualToDictionary:extraData.data]) {
+    return;
+  }
+
+  _lastActiveExtraData = extraData;
+  [self sendEventsInState:RNGestureHandlerStateActive forViewWithTag:sender.reactTag withExtraData:extraData];
+}
+
 - (void)handleTouchDown:(UIView *)sender forEvent:(UIEvent *)event
 {
   [self setCurrentPointerTypeForEvent:event];
@@ -202,11 +213,11 @@ - (void)handleTouchDown:(UIView *)sender forEvent:(UIEvent *)event
                                                        withNumberOfTouches:event.allTouches.count
                                                            withPointerType:_pointerType]];
 
-  [self sendEventsInState:RNGestureHandlerStateActive
-           forViewWithTag:sender.reactTag
-            withExtraData:[RNGestureHandlerEventExtraData forPointerInside:YES
-                                                       withNumberOfTouches:event.allTouches.count
-                                                           withPointerType:_pointerType]];
+  _lastActiveExtraData = nil;
+  [self sendActiveStateEventIfChangedForView:sender
+                                   extraData:[RNGestureHandlerEventExtraData forPointerInside:YES
+                                                                          withNumberOfTouches:event.allTouches.count
+                                                                              withPointerType:_pointerType]];
 }
 
 - (void)handleTouchUpOutside:(UIView *)sender forEvent:(UIEvent *)event
@@ -238,30 +249,27 @@ - (void)handleDragExit:(UIView *)sender forEvent:(UIEvent *)event
     UIControl *control = (UIControl *)sender;
     [control cancelTrackingWithEvent:event];
   } else {
-    [self sendEventsInState:RNGestureHandlerStateActive
-             forViewWithTag:sender.reactTag
-              withExtraData:[RNGestureHandlerEventExtraData forPointerInside:NO
-                                                         withNumberOfTouches:event.allTouches.count
-                                                             withPointerType:_pointerType]];
+    [self sendActiveStateEventIfChangedForView:sender
+                                     extraData:[RNGestureHandlerEventExtraData forPointerInside:NO
+                                                                            withNumberOfTouches:event.allTouches.count
+                                                                                withPointerType:_pointerType]];
   }
 }
 
 - (void)handleDragEnter:(UIView *)sender forEvent:(UIEvent *)event
 {
-  [self sendEventsInState:RNGestureHandlerStateActive
-           forViewWithTag:sender.reactTag
-            withExtraData:[RNGestureHandlerEventExtraData forPointerInside:YES
-                                                       withNumberOfTouches:event.allTouches.count
-                                                           withPointerType:_pointerType]];
+  [self sendActiveStateEventIfChangedForView:sender
+                                   extraData:[RNGestureHandlerEventExtraData forPointerInside:YES
+                                                                          withNumberOfTouches:event.allTouches.count
+                                                                              withPointerType:_pointerType]];
 }
 
 - (void)handleDragInside:(UIView *)sender forEvent:(UIEvent *)event
 {
-  [self sendEventsInState:RNGestureHandlerStateActive
-           forViewWithTag:sender.reactTag
-            withExtraData:[RNGestureHandlerEventExtraData forPointerInside:YES
-                                                       withNumberOfTouches:event.allTouches.count
-                                                           withPointerType:_pointerType]];
+  [self sendActiveStateEventIfChangedForView:sender
+                                   extraData:[RNGestureHandlerEventExtraData forPointerInside:YES
+                                                                          withNumberOfTouches:event.allTouches.count
+                                                                              withPointerType:_pointerType]];
 }
 
 - (void)handleDragOutside:(UIView *)sender forEvent:(UIEvent *)event
@@ -270,11 +278,10 @@ - (void)handleDragOutside:(UIView *)sender forEvent:(UIEvent *)event
     return;
   }
 
-  [self sendEventsInState:RNGestureHandlerStateActive
-           forViewWithTag:sender.reactTag
-            withExtraData:[RNGestureHandlerEventExtraData forPointerInside:NO
-                                                       withNumberOfTouches:event.allTouches.count
-                                                           withPointerType:_pointerType]];
+  [self sendActiveStateEventIfChangedForView:sender
+                                   extraData:[RNGestureHandlerEventExtraData forPointerInside:NO
+                                                                          withNumberOfTouches:event.allTouches.count
+                                                                              withPointerType:_pointerType]];
 }
 
 - (void)handleTouchCancel:(UIView *)sender forEvent:(UIEvent *)event

packages/react-native-gesture-handler/src/web/handlers/GestureHandler.ts

@@ -14,6 +14,7 @@ import { tagMessage } from '../../utils';
 import type {
   GestureStateChangeEventWithHandlerData,
   GestureUpdateEventWithHandlerData,
+  HandlerData,
   SingleGestureName,
 } from '../../v3/types';
 import type {
@@ -430,19 +431,21 @@ export default abstract class GestureHandler implements IGestureHandler {
       onGestureHandlerReanimatedStateChange,
     }: PropsRef = this.propsRef!.current;
 
+    const isStateChange = this.lastSentState !== newState;
+
     const resultEvent: ResultEvent = !usesNativeOrVirtualDetector(
       this.actionType
     )
       ? this.transformEventData(newState, oldState)
-      : this.lastSentState !== newState
+      : isStateChange
         ? this.transformStateChangeEvent(newState, oldState)
         : this.transformUpdateEvent(newState);
 
     // In the v2 API oldState field has to be undefined, unless we send event state changed
     // Here the order is flipped to avoid workarounds such as making backup of the state and setting it to undefined first, then changing it back
     // Flipping order with setting oldState to undefined solves issue, when events were being sent twice instead of once
     // However, this may cause trouble in the future (but for now we don't know that)
-    if (this.lastSentState !== newState) {
+    if (isStateChange) {
       this.lastSentState = newState;
 
       if (this.forReanimated) {
@@ -456,6 +459,16 @@ export default abstract class GestureHandler implements IGestureHandler {
       return;
     }
 
+    // Cover only V3 path due to different event shape
+    if (!isStateChange && usesNativeOrVirtualDetector(this.actionType)) {
+      const handlerData = (
+        resultEvent.nativeEvent as GestureUpdateEventWithHandlerData<unknown>
+      ).handlerData;
+      if (this.shouldSuppressActiveUpdate(handlerData)) {
+        return;
+      }
+    }
+
     (resultEvent.nativeEvent as GestureHandlerNativeEvent).oldState = undefined;
 
     if (this.forReanimated) {
@@ -467,6 +480,12 @@ export default abstract class GestureHandler implements IGestureHandler {
     }
   };
 
+  protected shouldSuppressActiveUpdate(
+    _handlerData: HandlerData<unknown>
+  ): boolean {
+    return false;
+  }
+
   private transformEventData(
     newState: State,
     oldState: State

packages/react-native-gesture-handler/src/web/handlers/NativeViewGestureHandler.ts

@@ -2,12 +2,16 @@ import { Platform } from 'react-native';
 
 import type { ActionType } from '../../ActionType';
 import { State } from '../../State';
+import { deepEqual } from '../../utils';
+import type { NativeHandlerData } from '../../v3/hooks/gestures/native/NativeTypes';
+import type { HandlerData } from '../../v3/types';
 import { SingleGestureName } from '../../v3/types';
 import { DEFAULT_TOUCH_SLOP } from '../constants';
 import type { AdaptedEvent, Config, PropsRef } from '../interfaces';
 import type { GestureHandlerDelegate } from '../tools/GestureHandlerDelegate';
 import GestureHandler from './GestureHandler';
 import type IGestureHandler from './IGestureHandler';
+
 export default class NativeViewGestureHandler extends GestureHandler {
   private buttonRole!: boolean;
 
@@ -20,6 +24,8 @@ export default class NativeViewGestureHandler extends GestureHandler {
   private startY = 0;
   private minDistSq = DEFAULT_TOUCH_SLOP * DEFAULT_TOUCH_SLOP;
 
+  private lastActiveHandlerData: HandlerData<NativeHandlerData> | null = null;
+
   public constructor(
     delegate: GestureHandlerDelegate<unknown, IGestureHandler>
   ) {
@@ -199,4 +205,22 @@ export default class NativeViewGestureHandler extends GestureHandler {
       ),
     };
   }
+
+  protected override shouldSuppressActiveUpdate(
+    handlerData: HandlerData<NativeHandlerData>
+  ): boolean {
+    if (
+      this.lastActiveHandlerData &&
+      deepEqual(this.lastActiveHandlerData, handlerData)
+    ) {
+      return true;
+    }
+    this.lastActiveHandlerData = handlerData;
+    return false;
+  }
+
+  public override reset(): void {
+    super.reset();
+    this.lastActiveHandlerData = null;
+  }
 }