Add numberOfPointers to LongPress

android/src/main/java/com/swmansion/gesturehandler/core/LongPressGestureHandler.kt

@@ -12,18 +12,21 @@ class LongPressGestureHandler(context: Context) : GestureHandler<LongPressGestur
     get() = (previousTime - startTime).toInt()
   private val defaultMaxDistSq: Float
   private var maxDistSq: Float
+  private var numberOfPointersRequired: Int
   private var startX = 0f
   private var startY = 0f
   private var startTime: Long = 0
   private var previousTime: Long = 0
   private var handler: Handler? = null
+  private var currentPointers = 0
 
   init {
     setShouldCancelWhenOutside(true)
 
     val defaultMaxDist = DEFAULT_MAX_DIST_DP * context.resources.displayMetrics.density
     defaultMaxDistSq = defaultMaxDist * defaultMaxDist
     maxDistSq = defaultMaxDistSq
+    numberOfPointersRequired = 1
   }
 
   override fun resetConfig() {
@@ -37,6 +40,47 @@ class LongPressGestureHandler(context: Context) : GestureHandler<LongPressGestur
     return this
   }
 
+  fun setNumberOfPointers(numberOfPointers: Int): LongPressGestureHandler {
+    numberOfPointersRequired = numberOfPointers
+    return this
+  }
+
+  private fun getAverageX(ev: MotionEvent, excludePointer: Boolean = false): Float {
+    if (!excludePointer) {
+      return (0 until ev.pointerCount).map { ev.getX(it) }.average().toFloat()
+    }
+
+    var sumX = 0f
+
+    for (i in 0 until ev.pointerCount) {
+      if (i == ev.actionIndex) {
+        continue
+      }
+
+      sumX += ev.getX(i)
+    }
+
+    return sumX / (ev.pointerCount - 1)
+  }
+
+  private fun getAverageY(ev: MotionEvent, excludePointer: Boolean = false): Float {
+    if (!excludePointer) {
+      return (0 until ev.pointerCount).map { ev.getY(it) }.average().toFloat()
+    }
+
+    var sumY = 0f
+
+    for (i in 0 until ev.pointerCount) {
+      if (i == ev.actionIndex) {
+        continue
+      }
+
+      sumY += ev.getY(i)
+    }
+
+    return sumY / (ev.pointerCount - 1)
+  }
+
   override fun onHandle(event: MotionEvent, sourceEvent: MotionEvent) {
     if (!shouldActivateWithMouse(sourceEvent)) {
       return
@@ -46,8 +90,25 @@ class LongPressGestureHandler(context: Context) : GestureHandler<LongPressGestur
       previousTime = SystemClock.uptimeMillis()
       startTime = previousTime
       begin()
-      startX = sourceEvent.rawX
-      startY = sourceEvent.rawY
+      startX = getAverageX(sourceEvent)
+      startY = getAverageY(sourceEvent)
+
+      currentPointers++
+    }
+
+    if (sourceEvent.actionMasked == MotionEvent.ACTION_POINTER_DOWN) {
+      currentPointers++
+
+      startX = getAverageX(sourceEvent)
+      startY = getAverageY(sourceEvent)
+
+      if (currentPointers > numberOfPointersRequired) {
+        fail()
+        currentPointers = 0
+      }
+    }
+
+    if (state == STATE_BEGAN && currentPointers == numberOfPointersRequired && (sourceEvent.actionMasked == MotionEvent.ACTION_DOWN || sourceEvent.actionMasked == MotionEvent.ACTION_POINTER_DOWN)) {
       handler = Handler(Looper.getMainLooper())
       if (minDurationMs > 0) {
         handler!!.postDelayed({ activate() }, minDurationMs)
@@ -56,20 +117,37 @@ class LongPressGestureHandler(context: Context) : GestureHandler<LongPressGestur
       }
     }
     if (sourceEvent.actionMasked == MotionEvent.ACTION_UP || sourceEvent.actionMasked == MotionEvent.ACTION_BUTTON_RELEASE) {
+      currentPointers--
+
       handler?.let {
         it.removeCallbacksAndMessages(null)
         handler = null
       }
+
       if (state == STATE_ACTIVE) {
         end()
       } else {
         fail()
       }
+    } else if (sourceEvent.actionMasked == MotionEvent.ACTION_POINTER_UP) {
+      currentPointers--
+
+      if (currentPointers < numberOfPointersRequired && state != STATE_ACTIVE) {
+        fail()
+        currentPointers = 0
+      } else {
+        startX = getAverageX(sourceEvent, true)
+        startY = getAverageY(sourceEvent, true)
+      }
     } else {
       // calculate distance from start
-      val deltaX = sourceEvent.rawX - startX
-      val deltaY = sourceEvent.rawY - startY
+      val x = getAverageX(sourceEvent)
+      val y = getAverageY(sourceEvent)
+
+      val deltaX = x - startX
+      val deltaY = y - startY
       val distSq = deltaX * deltaX + deltaY * deltaY
+
       if (distSq > maxDistSq) {
         if (state == STATE_ACTIVE) {
           cancel()

android/src/main/java/com/swmansion/gesturehandler/react/RNGestureHandlerModule.kt

@@ -154,6 +154,9 @@ class RNGestureHandlerModule(reactContext: ReactApplicationContext?) :
       if (config.hasKey(KEY_LONG_PRESS_MAX_DIST)) {
         handler.setMaxDist(PixelUtil.toPixelFromDIP(config.getDouble(KEY_LONG_PRESS_MAX_DIST)))
       }
+      if (config.hasKey(KEY_NUMBER_OF_POINTERS)) {
+        handler.setNumberOfPointers(config.getInt(KEY_NUMBER_OF_POINTERS))
+      }
     }
 
     override fun createEventBuilder(handler: LongPressGestureHandler) = LongPressGestureHandlerEventDataBuilder(handler)

apple/Handlers/RNLongPressHandler.m

@@ -26,6 +26,7 @@ @interface RNBetterLongPressGestureRecognizer : NSGestureRecognizer {
 #if TARGET_OS_OSX
 @property (nonatomic, assign) double minimumPressDuration;
 @property (nonatomic, assign) double allowableMovement;
+@property (nonatomic, assign) double numberOfTouchesRequired;
 #endif
 
 - (id)initWithGestureHandler:(RNGestureHandler *)gestureHandler;
@@ -77,6 +78,8 @@ - (void)touchesBegan:(NSSet<RNGHUITouch *> *)touches withEvent:(UIEvent *)event
   [super touchesBegan:touches withEvent:event];
   [_gestureHandler.pointerTracker touchesBegan:touches withEvent:event];
 
+  self.state = UIGestureRecognizerStatePossible;
+
   _initPosition = [self locationInView:self.view];
   startTime = CACurrentMediaTime();
   [_gestureHandler reset];
@@ -89,6 +92,7 @@ - (void)touchesMoved:(NSSet<RNGHUITouch *> *)touches withEvent:(UIEvent *)event
   [_gestureHandler.pointerTracker touchesMoved:touches withEvent:event];
 
   if ([self shouldCancelGesture]) {
+    self.state = UIGestureRecognizerStateFailed;
     self.enabled = NO;
     self.enabled = YES;
   }
@@ -228,6 +232,11 @@ - (void)configure:(NSDictionary *)config
   if (prop != nil) {
     recognizer.allowableMovement = [RCTConvert CGFloat:prop];
   }
+
+  prop = config[@"numberOfPointers"];
+  if (prop != nil) {
+    recognizer.numberOfTouchesRequired = [RCTConvert CGFloat:prop];
+  }
 }
 
 #if !TARGET_OS_OSX

src/handlers/LongPressGestureHandler.ts

@@ -8,6 +8,7 @@ import {
 export const longPressGestureHandlerProps = [
   'minDurationMs',
   'maxDist',
+  'numberOfPointers',
 ] as const;
 
 export interface LongPressGestureConfig {
@@ -24,6 +25,11 @@ export interface LongPressGestureConfig {
    * will fail to recognize the gesture. The default value is 10.
    */
   maxDist?: number;
+
+  /**
+   * Determine exact number of points required to handle the long press gesture.
+   */
+  numberOfPointers?: number;
 }
 
 export interface LongPressGestureHandlerProps

src/handlers/gestures/longPressGesture.ts

@@ -31,6 +31,15 @@ export class LongPressGesture extends BaseGesture<LongPressGestureHandlerEventPa
     this.config.maxDist = distance;
     return this;
   }
+
+  /**
+   * Determine exact number of points required to handle the long press gesture.
+   * @param pointers
+   */
+  numberOfPointers(pointers: number) {
+    this.config.numberOfPointers = pointers;
+    return this;
+  }
 }
 
 export type LongPressGestureType = InstanceType<typeof LongPressGesture>;

src/web/handlers/LongPressGestureHandler.ts

@@ -12,6 +12,7 @@ export default class LongPressGestureHandler extends GestureHandler {
   private defaultMaxDistSq = DEFAULT_MAX_DIST_DP * SCALING_FACTOR;
 
   private maxDistSq = this.defaultMaxDistSq;
+  private numberOfPointers = 1;
   private startX = 0;
   private startY = 0;
 
@@ -45,6 +46,10 @@ export default class LongPressGestureHandler extends GestureHandler {
     if (this.config.maxDist !== undefined) {
       this.maxDistSq = this.config.maxDist * this.config.maxDist;
     }
+
+    if (this.config.numberOfPointers !== undefined) {
+      this.numberOfPointers = this.config.numberOfPointers;
+    }
   }
 
   protected resetConfig(): void {
@@ -64,17 +69,31 @@ export default class LongPressGestureHandler extends GestureHandler {
 
     this.tracker.addToTracker(event);
     super.onPointerDown(event);
-    this.tryBegin(event);
+
+    this.startX = event.x;
+    this.startY = event.y;
+
+    this.tryBegin();
     this.tryActivate();
-    this.checkDistanceFail(event);
 
     this.tryToSendTouchEvent(event);
   }
+  protected onPointerAdd(event: AdaptedEvent): void {
+    super.onPointerAdd(event);
+    this.tracker.addToTracker(event);
+
+    const absoluteCoordsAverage = this.tracker.getAbsoluteCoordsAverage();
+
+    this.startX = absoluteCoordsAverage.x;
+    this.startY = absoluteCoordsAverage.y;
+
+    this.tryActivate();
+  }
 
   protected onPointerMove(event: AdaptedEvent): void {
     super.onPointerMove(event);
     this.tracker.track(event);
-    this.checkDistanceFail(event);
+    this.checkDistanceFail();
   }
 
   protected onPointerUp(event: AdaptedEvent): void {
@@ -88,7 +107,19 @@ export default class LongPressGestureHandler extends GestureHandler {
     }
   }
 
-  private tryBegin(event: AdaptedEvent): void {
+  protected onPointerRemove(event: AdaptedEvent): void {
+    super.onPointerRemove(event);
+    this.tracker.removeFromTracker(event.pointerId);
+
+    if (
+      this.tracker.getTrackedPointersCount() < this.numberOfPointers &&
+      this.getState() !== State.ACTIVE
+    ) {
+      this.fail();
+    }
+  }
+
+  private tryBegin(): void {
     if (this.currentState !== State.UNDETERMINED) {
       return;
     }
@@ -97,12 +128,13 @@ export default class LongPressGestureHandler extends GestureHandler {
     this.startTime = this.previousTime;
 
     this.begin();
-
-    this.startX = event.x;
-    this.startY = event.y;
   }
 
   private tryActivate(): void {
+    if (this.tracker.getTrackedPointersCount() !== this.numberOfPointers) {
+      return;
+    }
+
     if (this.minDurationMs > 0) {
       this.activationTimeout = setTimeout(() => {
         this.activate();
@@ -112,9 +144,11 @@ export default class LongPressGestureHandler extends GestureHandler {
     }
   }
 
-  private checkDistanceFail(event: AdaptedEvent): void {
-    const dx = event.x - this.startX;
-    const dy = event.y - this.startY;
+  private checkDistanceFail(): void {
+    const absoluteCoordsAverage = this.tracker.getAbsoluteCoordsAverage();
+
+    const dx = absoluteCoordsAverage.x - this.startX;
+    const dy = absoluteCoordsAverage.y - this.startY;
     const distSq = dx * dx + dy * dy;
 
     if (distSq <= this.maxDistSq) {