feat(gestures): GestureEvents.gestureAttached added to modify native recognizers when needed

packages/core/ui/gestures/gestures-common.ts

@@ -1,6 +1,10 @@
 import { GestureEventData, GesturesObserver as GesturesObserverDefinition } from '.';
 import { View } from '../core/view';
 
+export enum GestureEvents {
+	gestureAttached = 'gestureAttached',
+}
+
 export enum GestureTypes {
 	tap = 1 << 0,
 	doubleTap = 1 << 1,

packages/core/ui/gestures/index.android.ts

@@ -4,7 +4,7 @@ import { View } from '../core/view';
 import { EventData } from '../../data/observable';
 
 // Types.
-import { GesturesObserverBase, toString, TouchAction, GestureStateTypes, GestureTypes, SwipeDirection } from './gestures-common';
+import { GesturesObserverBase, toString, TouchAction, GestureStateTypes, GestureTypes, SwipeDirection, GestureEvents } from './gestures-common';
 
 // Import layout from utils directly to avoid circular references
 import { layout } from '../../utils';
@@ -297,31 +297,41 @@ export class GesturesObserver extends GesturesObserverBase {
 	private _attach(target: View, type: GestureTypes) {
 		this._detach();
 
+		let recognizer;
+
 		if (type & GestureTypes.tap || type & GestureTypes.doubleTap || type & GestureTypes.longPress) {
 			initializeTapAndDoubleTapGestureListener();
-			this._simpleGestureDetector = <any>new androidx.core.view.GestureDetectorCompat(target._context, new TapAndDoubleTapGestureListener(this, this.target, type));
+			recognizer = this._simpleGestureDetector = <any>new androidx.core.view.GestureDetectorCompat(target._context, new TapAndDoubleTapGestureListener(this, this.target, type));
 		}
 
 		if (type & GestureTypes.pinch) {
 			initializePinchGestureListener();
-			this._scaleGestureDetector = new android.view.ScaleGestureDetector(target._context, new PinchGestureListener(this, this.target));
+			recognizer = this._scaleGestureDetector = new android.view.ScaleGestureDetector(target._context, new PinchGestureListener(this, this.target));
 		}
 
 		if (type & GestureTypes.swipe) {
 			initializeSwipeGestureListener();
-			this._swipeGestureDetector = <any>new androidx.core.view.GestureDetectorCompat(target._context, new SwipeGestureListener(this, this.target));
+			recognizer = this._swipeGestureDetector = <any>new androidx.core.view.GestureDetectorCompat(target._context, new SwipeGestureListener(this, this.target));
 		}
 
 		if (type & GestureTypes.pan) {
-			this._panGestureDetector = new CustomPanGestureDetector(this, this.target);
+			recognizer = this._panGestureDetector = new CustomPanGestureDetector(this, this.target);
 		}
 
 		if (type & GestureTypes.rotation) {
-			this._rotateGestureDetector = new CustomRotateGestureDetector(this, this.target);
+			recognizer = this._rotateGestureDetector = new CustomRotateGestureDetector(this, this.target);
 		}
 
 		if (type & GestureTypes.touch) {
 			this._notifyTouch = true;
+		} else {
+			this.target.notify({
+				eventName: GestureEvents.gestureAttached,
+				object: this.target,
+				type,
+				view: this.target,
+				ios: recognizer,
+			});
 		}
 	}
 

packages/core/ui/gestures/index.d.ts

@@ -1,6 +1,17 @@
 import { View } from '../core/view';
 import { EventData } from '../../data/observable';
 
+/**
+ * Events emitted during gesture lifecycle
+ */
+export enum GestureEvents {
+	/**
+	 * When the gesture is attached to the view
+	 * Provides access to the native gesture recognizer for further customization
+	 */
+	gestureAttached = 'gestureAttached',
+}
+
 /**
  * Defines an enum with supported gesture types.
  */

packages/core/ui/gestures/index.ios.ts

@@ -5,7 +5,7 @@ import { View } from '../core/view';
 import { EventData } from '../../data/observable';
 
 // Types.
-import { GesturesObserverBase, toString, TouchAction, GestureStateTypes, GestureTypes, SwipeDirection } from './gestures-common';
+import { GesturesObserverBase, toString, TouchAction, GestureStateTypes, GestureTypes, SwipeDirection, GestureEvents } from './gestures-common';
 
 // Import layout from utils directly to avoid circular references
 import { layout } from '../../utils';
@@ -306,6 +306,14 @@ export class GesturesObserver extends GesturesObserverBase {
 					target: target,
 				};
 			}
+
+			this.target.notify({
+				eventName: GestureEvents.gestureAttached,
+				object: this.target,
+				type,
+				view: this.target,
+				ios: recognizer,
+			});
 		}
 
 		return recognizer;
@@ -348,7 +356,7 @@ function _getUIGestureRecognizerType(type: GestureTypes): any {
 function getState(recognizer: UIGestureRecognizer) {
 	if (recognizer.state === UIGestureRecognizerState.Began) {
 		return GestureStateTypes.began;
-	} else if (recognizer.state === UIGestureRecognizerState.Cancelled) {
+	} else if (recognizer.state === UIGestureRecognizerState.Cancelled || recognizer.state === UIGestureRecognizerState.Failed) {
 		return GestureStateTypes.cancelled;
 	} else if (recognizer.state === UIGestureRecognizerState.Changed) {
 		return GestureStateTypes.changed;

packages/core/ui/index.ts

@@ -27,7 +27,7 @@ export * from './editable-text-base';
 export { Frame, setActivityCallbacks } from './frame';
 export type { NavigationEntry, NavigationContext, NavigationTransition, BackstackEntry, ViewEntry, AndroidActivityCallbacks } from './frame';
 
-export { GesturesObserver, TouchAction, GestureTypes, GestureStateTypes, SwipeDirection } from './gestures';
+export { GesturesObserver, TouchAction, GestureTypes, GestureStateTypes, SwipeDirection, GestureEvents } from './gestures';
 export type { GestureEventData, GestureEventDataWithState, TapGestureEventData, PanGestureEventData, PinchGestureEventData, RotationGestureEventData, SwipeGestureEventData, TouchGestureEventData } from './gestures';
 
 export { HtmlView } from './html-view';