diff --git a/packages/core/application/application-interfaces.ts b/packages/core/application/application-interfaces.ts
index 895c7c433..a1bc99071 100644
--- a/packages/core/application/application-interfaces.ts
+++ b/packages/core/application/application-interfaces.ts
@@ -71,8 +71,22 @@ export interface CssChangedEventData<T extends Observable = Observable> extends
 }
 
 export interface AndroidActivityEventData<T extends Observable = Observable> extends ApplicationEventData<T> {
-	activity: any /* androidx.appcompat.app.AppCompatActivity */;
-	object: any /* AndroidApplication */;
+	/**
+	 * The activity.
+	 * androidx.appcompat.app.AppCompatActivity
+	 */
+	activity: any;
+
+	/**
+	 * The name of the event.
+	 */
+	eventName: string;
+
+	/**
+	 * The instance that has raised the event.
+	 * AndroidApplication
+	 */
+	object: T;
 }
 
 export interface AndroidActivityBundleEventData<T extends Observable = Observable> extends AndroidActivityEventData<T> {
diff --git a/packages/core/application/index.d.ts b/packages/core/application/index.d.ts
index 6deba59fd..31c3eeaff 100644
--- a/packages/core/application/index.d.ts
+++ b/packages/core/application/index.d.ts
@@ -395,7 +395,7 @@ export let ios: iOSApplication;
 /**
  * Data for the Android activity events.
  */
-export interface AndroidActivityEventData {
+export interface AndroidActivityEventData<T extends Observable = Observable> extends ApplicationEventData<T> {
 	/**
 	 * The activity.
 	 */
diff --git a/packages/core/ui/button/index.d.ts b/packages/core/ui/button/index.d.ts
index 9e4a6d0b2..767eb480e 100644
--- a/packages/core/ui/button/index.d.ts
+++ b/packages/core/ui/button/index.d.ts
@@ -31,10 +31,10 @@ export class Button extends TextBase {
 	 * @param callback - Callback function which will be executed when event is raised.
 	 * @param thisArg - An optional parameter which will be used as `this` context for callback execution.
 	 */
-	on<T extends Observable = Observable>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = Button>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Raised when a tap event occurs.
 	 */
-	on<T extends Observable = Observable>(event: 'tap', callback: (args: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = Button>(event: 'tap', callback: (args: EventData<T>) => void, thisArg?: any): void;
 }
diff --git a/packages/core/ui/core/view/index.android.ts b/packages/core/ui/core/view/index.android.ts
index 42f254dcd..527fe47ad 100644
--- a/packages/core/ui/core/view/index.android.ts
+++ b/packages/core/ui/core/view/index.android.ts
@@ -335,14 +335,14 @@ export class View extends ViewCommon {
 	}
 
 	// TODO: Implement unobserve that detach the touchListener.
-	_observe<T extends Observable = Observable>(type: GestureTypes, callback: (args: GestureEventData<T>) => void, thisArg?: any): void {
+	_observe<T extends Observable = View>(type: GestureTypes, callback: (args: GestureEventData<T>) => void, thisArg?: any): void {
 		super._observe(type, callback, thisArg);
 		if (this.isLoaded && !this.touchListenerIsSet) {
 			this.setOnTouchListener();
 		}
 	}
 
-	on<T extends Observable = Observable>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any) {
+	on<T extends Observable = View>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any) {
 		super.on(eventNames, callback, thisArg);
 		const isLayoutEvent = typeof eventNames === 'string' ? eventNames.indexOf(ViewCommon.layoutChangedEvent) !== -1 : false;
 
@@ -351,7 +351,7 @@ export class View extends ViewCommon {
 		}
 	}
 
-	off<T extends Observable = Observable>(eventNames: string, callback?: (data: EventData<T>) => void, thisArg?: any) {
+	off<T extends Observable = View>(eventNames: string, callback?: (data: EventData<T>) => void, thisArg?: any) {
 		super.off(eventNames, callback, thisArg);
 		const isLayoutEvent = typeof eventNames === 'string' ? eventNames.indexOf(ViewCommon.layoutChangedEvent) !== -1 : false;
 
diff --git a/packages/core/ui/core/view/index.d.ts b/packages/core/ui/core/view/index.d.ts
index 947421bb1..a95087768 100644
--- a/packages/core/ui/core/view/index.d.ts
+++ b/packages/core/ui/core/view/index.d.ts
@@ -83,7 +83,7 @@ export interface Size {
 /**
  * Defines the data for the shownModally event.
  */
-export interface ShownModallyData<T extends Observable = Observable> extends EventData<T> {
+export interface ShownModallyData<T extends Observable = ViewCommon> extends EventData<T> {
 	/**
 	 * The context (optional, may be undefined) passed to the view when shown modally.
 	 */
@@ -585,7 +585,7 @@ export abstract class View extends ViewCommon {
 	 * @param callback An optional parameter pointing to a specific listener. If not defined, all listeners for the event names will be removed.
 	 * @param thisArg An optional parameter which when set will be used to refine search of the correct callback which will be removed as event listener.
 	 */
-	off<T extends Observable = Observable>(eventNames: string | GestureTypes, callback?: (args: EventData<T>) => void, thisArg?: any);
+	off<T extends Observable = View>(eventNames: string | GestureTypes, callback?: (args: EventData<T>) => void, thisArg?: any);
 
 	/**
 	 * A basic method signature to hook an event listener (shortcut alias to the addEventListener method).
@@ -593,33 +593,33 @@ export abstract class View extends ViewCommon {
 	 * @param callback - Callback function which will be executed when event is raised.
 	 * @param thisArg - An optional parameter which will be used as `this` context for callback execution.
 	 */
-	on<T extends Observable = Observable>(eventNames: string | GestureTypes, callback: (args: EventData<T>) => void, thisArg?: any);
+	on<T extends Observable = View>(eventNames: string | GestureTypes, callback: (args: EventData<T>) => void, thisArg?: any);
 
 	/**
 	 * Raised when a loaded event occurs.
 	 */
-	on<T extends Observable = Observable>(event: 'loaded', callback: (args: EventData<T>) => void, thisArg?: any);
+	on<T extends Observable = View>(event: 'loaded', callback: (args: EventData<T>) => void, thisArg?: any);
 
 	/**
 	 * Raised when an unloaded event occurs.
 	 */
-	on<T extends Observable = Observable>(event: 'unloaded', callback: (args: EventData<T>) => void, thisArg?: any);
+	on<T extends Observable = View>(event: 'unloaded', callback: (args: EventData<T>) => void, thisArg?: any);
 
 	/**
 	 * Raised when a back button is pressed.
 	 * This event is raised only for android.
 	 */
-	on<T extends Observable = Observable>(event: 'androidBackPressed', callback: (args: EventData<T>) => void, thisArg?: any);
+	on<T extends Observable = View>(event: 'androidBackPressed', callback: (args: EventData<T>) => void, thisArg?: any);
 
 	/**
 	 * Raised before the view is shown as a modal dialog.
 	 */
-	on<T extends Observable = Observable>(event: 'showingModally', callback: (args: ShownModallyData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = View>(event: 'showingModally', callback: (args: ShownModallyData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Raised after the view is shown as a modal dialog.
 	 */
-	on<T extends Observable = Observable>(event: 'shownModally', callback: (args: ShownModallyData<T>) => void, thisArg?: any);
+	on<T extends Observable = View>(event: 'shownModally', callback: (args: ShownModallyData<T>) => void, thisArg?: any);
 
 	/**
 	 * Returns the current modal view that this page is showing (is parent of), if any.
diff --git a/packages/core/ui/core/view/view-common.ts b/packages/core/ui/core/view/view-common.ts
index 6464b9b32..d54282d55 100644
--- a/packages/core/ui/core/view/view-common.ts
+++ b/packages/core/ui/core/view/view-common.ts
@@ -253,7 +253,7 @@ export abstract class ViewCommon extends ViewBase implements ViewDefinition {
 		}
 	}
 
-	_observe<T extends Observable = Observable>(type: GestureTypes, callback: (args: GestureEventData<T>) => void, thisArg?: any): void {
+	_observe<T extends Observable = ViewCommon>(type: GestureTypes, callback: (args: GestureEventData<T>) => void, thisArg?: any): void {
 		if (!this._gestureObservers[type]) {
 			this._gestureObservers[type] = [];
 		}
@@ -265,7 +265,7 @@ export abstract class ViewCommon extends ViewBase implements ViewDefinition {
 		return this._gestureObservers[type];
 	}
 
-	public addEventListener<T extends Observable = Observable>(arg: string | GestureTypes, callback: (data: EventData<T>) => void, thisArg?: any) {
+	public addEventListener<T extends Observable = ViewCommon>(arg: string | GestureTypes, callback: (data: EventData<T>) => void, thisArg?: any) {
 		if (typeof arg === 'string') {
 			arg = getEventOrGestureName(arg);
 
@@ -293,7 +293,7 @@ export abstract class ViewCommon extends ViewBase implements ViewDefinition {
 		}
 	}
 
-	public removeEventListener<T extends Observable = Observable>(arg: string | GestureTypes, callback?: (data: EventData<T>) => void, thisArg?: any) {
+	public removeEventListener<T extends Observable = ViewCommon>(arg: string | GestureTypes, callback?: (data: EventData<T>) => void, thisArg?: any) {
 		if (typeof arg === 'string') {
 			const gesture = gestureFromString(arg);
 			if (gesture && !this._isEvent(arg)) {
diff --git a/packages/core/ui/frame/index.d.ts b/packages/core/ui/frame/index.d.ts
index 2fd89be4f..41da5ac52 100644
--- a/packages/core/ui/frame/index.d.ts
+++ b/packages/core/ui/frame/index.d.ts
@@ -6,7 +6,7 @@ import { Transition } from '../transition';
 
 export * from './frame-interfaces';
 
-export interface NavigationData<T extends Observable = Observable> extends EventData<T> {
+export interface NavigationData<T extends Observable = Frame> extends EventData<T> {
 	entry?: NavigationEntry;
 	fromEntry?: NavigationEntry;
 	isBack?: boolean;
@@ -221,17 +221,17 @@ export class Frame extends FrameBase {
 	 * @param callback - Callback function which will be executed when event is raised.
 	 * @param thisArg - An optional parameter which will be used as `this` context for callback execution.
 	 */
-	on<T extends Observable = Observable>(eventNames: string, callback: (args: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = Frame>(eventNames: string, callback: (args: EventData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Raised when navigation to the page has started.
 	 */
-	public on<T extends Observable = Observable>(event: 'navigatingTo', callback: (args: NavigationData<T>) => void, thisArg?: any): void;
+	public on<T extends Observable = Frame>(event: 'navigatingTo', callback: (args: NavigationData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Raised when navigation to the page has finished.
 	 */
-	public on<T extends Observable = Observable>(event: 'navigatedTo', callback: (args: NavigationData<T>) => void, thisArg?: any): void;
+	public on<T extends Observable = Frame>(event: 'navigatedTo', callback: (args: NavigationData<T>) => void, thisArg?: any): void;
 }
 
 /**
diff --git a/packages/core/ui/gestures/index.d.ts b/packages/core/ui/gestures/index.d.ts
index b1a34e6fb..759d2931e 100644
--- a/packages/core/ui/gestures/index.d.ts
+++ b/packages/core/ui/gestures/index.d.ts
@@ -132,7 +132,7 @@ export namespace TouchAction {
 /**
  * Provides gesture event data.
  */
-export interface GestureEventData<T extends Observable = Observable> extends EventData<T> {
+export interface GestureEventData<T extends Observable = View> extends EventData<T> {
 	/**
 	 * Gets the type of the gesture.
 	 */
@@ -154,7 +154,7 @@ export interface GestureEventData<T extends Observable = Observable> extends Eve
 /**
  * Provides gesture event data.
  */
-export interface TapGestureEventData<T extends Observable = Observable> extends GestureEventData<T> {
+export interface TapGestureEventData<T extends Observable = View> extends GestureEventData<T> {
 	/**
 	 * Gets the number of pointers in the event.
 	 */
@@ -172,7 +172,7 @@ export interface TapGestureEventData<T extends Observable = Observable> extends
 /**
  * Provides gesture event data.
  */
-export interface TouchGestureEventData<T extends Observable = Observable> extends TapGestureEventData<T> {
+export interface TouchGestureEventData<T extends Observable = View> extends TapGestureEventData<T> {
 	/**
 	 * Gets action of the touch. Possible values: 'up', 'move', 'down', 'cancel'
 	 */
@@ -241,14 +241,14 @@ export interface Pointer {
 /**
  * Provides gesture event data.
  */
-export interface GestureEventDataWithState<T extends Observable = Observable> extends GestureEventData<T> {
+export interface GestureEventDataWithState<T extends Observable = View> extends GestureEventData<T> {
 	state: number;
 }
 
 /**
  * Provides gesture event data for pinch gesture.
  */
-export interface PinchGestureEventData<T extends Observable = Observable> extends GestureEventDataWithState<T> {
+export interface PinchGestureEventData<T extends Observable = View> extends GestureEventDataWithState<T> {
 	scale: number;
 
 	getFocusX(): number;
@@ -258,14 +258,14 @@ export interface PinchGestureEventData<T extends Observable = Observable> extend
 /**
  * Provides gesture event data for swipe gesture.
  */
-export interface SwipeGestureEventData<T extends Observable = Observable> extends GestureEventData<T> {
+export interface SwipeGestureEventData<T extends Observable = View> extends GestureEventData<T> {
 	direction: SwipeDirection;
 }
 
 /**
  * Provides gesture event data for pan gesture.
  */
-export interface PanGestureEventData<T extends Observable = Observable> extends GestureEventDataWithState<T> {
+export interface PanGestureEventData<T extends Observable = View> extends GestureEventDataWithState<T> {
 	deltaX: number;
 	deltaY: number;
 }
@@ -273,14 +273,14 @@ export interface PanGestureEventData<T extends Observable = Observable> extends
 /**
  * Provides gesture event data for rotation gesture.
  */
-export interface RotationGestureEventData<T extends Observable = Observable> extends GestureEventDataWithState<T> {
+export interface RotationGestureEventData<T extends Observable = View> extends GestureEventDataWithState<T> {
 	rotation: number;
 }
 
 /**
  * Provides options for the GesturesObserver.
  */
-export class GesturesObserver<T extends Observable = Observable> {
+export class GesturesObserver<T extends Observable = View> {
 	/**
 	 * Creates an instance of GesturesObserver class.
 	 * @param target - The view for which the observer is created.
@@ -328,7 +328,7 @@ export class GesturesObserver<T extends Observable = Observable> {
  * @param callback - A function that will be executed when a gesture is received.
  * @param context - this argument for the callback.
  */
-export function observe<T extends Observable = Observable>(target: View, type: GestureTypes, callback: (args: GestureEventData<T>) => void, context?: any): GesturesObserver<T>;
+export function observe<T extends Observable = View>(target: View, type: GestureTypes, callback: (args: GestureEventData<T>) => void, context?: any): GesturesObserver<T>;
 
 /**
  * Returns a string representation of a gesture type.
diff --git a/packages/core/ui/gestures/index.ios.ts b/packages/core/ui/gestures/index.ios.ts
index bcf959662..28ba4ecbb 100644
--- a/packages/core/ui/gestures/index.ios.ts
+++ b/packages/core/ui/gestures/index.ios.ts
@@ -53,7 +53,7 @@ class UIGestureRecognizerImpl extends NSObject {
 	private _callback: Function;
 	private _context: any;
 
-	public static initWithOwnerTypeCallback<T extends Observable = Observable>(owner: WeakRef<GesturesObserver>, type: any, callback?: (args: GestureEventData<T>) => void, thisArg?: any): UIGestureRecognizerImpl {
+	public static initWithOwnerTypeCallback<T extends Observable = View>(owner: WeakRef<GesturesObserver>, type: any, callback?: (args: GestureEventData<T>) => void, thisArg?: any): UIGestureRecognizerImpl {
 		const handler = <UIGestureRecognizerImpl>UIGestureRecognizerImpl.new();
 		handler._owner = owner;
 		handler._type = type;
@@ -320,7 +320,7 @@ export class GesturesObserver extends GesturesObserverBase {
 	}
 }
 
-function _createUIGestureRecognizerTarget<T extends Observable = Observable>(owner: GesturesObserver, type: GestureTypes, callback?: (args: GestureEventData<T>) => void, context?: any): any {
+function _createUIGestureRecognizerTarget<T extends Observable = View>(owner: GesturesObserver, type: GestureTypes, callback?: (args: GestureEventData<T>) => void, context?: any): any {
 	return UIGestureRecognizerImpl.initWithOwnerTypeCallback(new WeakRef(owner), type, callback, context);
 }
 
diff --git a/packages/core/ui/image-cache/image-cache-common.ts b/packages/core/ui/image-cache/image-cache-common.ts
index 402ff774a..6abab86c1 100644
--- a/packages/core/ui/image-cache/image-cache-common.ts
+++ b/packages/core/ui/image-cache/image-cache-common.ts
@@ -215,7 +215,7 @@ export class Cache extends Observable implements definition.Cache {
 	}
 }
 export interface Cache {
-	on<T extends Observable = Observable>(eventNames: string, callback: (args: EventData<T>) => void, thisArg?: any): void;
-	on<T extends Observable = Observable>(event: 'downloaded', callback: (args: definition.DownloadedData<T>) => void, thisArg?: any): void;
-	on<T extends Observable = Observable>(event: 'downloadError', callback: (args: definition.DownloadError<T>) => void, thisArg?: any): void;
+	on<T extends Observable = Cache>(eventNames: string, callback: (args: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = Cache>(event: 'downloaded', callback: (args: definition.DownloadedData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = Cache>(event: 'downloadError', callback: (args: definition.DownloadError<T>) => void, thisArg?: any): void;
 }
diff --git a/packages/core/ui/image-cache/index.d.ts b/packages/core/ui/image-cache/index.d.ts
index d94c1c604..468567fa7 100644
--- a/packages/core/ui/image-cache/index.d.ts
+++ b/packages/core/ui/image-cache/index.d.ts
@@ -85,17 +85,17 @@ export class Cache extends Observable {
 	 * @param callback - Callback function which will be executed when event is raised.
 	 * @param thisArg - An optional parameter which will be used as `this` context for callback execution.
 	 */
-	on<T extends Observable = Observable>(eventNames: string, callback: (args: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = Cache>(eventNames: string, callback: (args: EventData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Raised when the image has been downloaded.
 	 */
-	on<T extends Observable = Observable>(event: 'downloaded', callback: (args: DownloadedData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = Cache>(event: 'downloaded', callback: (args: DownloadedData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Raised if the image download errors.
 	 */
-	on<T extends Observable = Observable>(event: 'downloadError', callback: (args: DownloadError<T>) => void, thisArg?: any): void;
+	on<T extends Observable = Cache>(event: 'downloadError', callback: (args: DownloadError<T>) => void, thisArg?: any): void;
 
 	//@private
 	/**
diff --git a/packages/core/ui/list-view/index.d.ts b/packages/core/ui/list-view/index.d.ts
index f230c8d75..525967be6 100644
--- a/packages/core/ui/list-view/index.d.ts
+++ b/packages/core/ui/list-view/index.d.ts
@@ -108,7 +108,7 @@ export class ListView extends View {
 	 * @param callback - Callback function which will be executed when event is raised.
 	 * @param thisArg - An optional parameter which will be used as `this` context for callback execution.
 	 */
-	on<T extends Observable = Observable>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = ListView>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Raised when a View for the data at the specified index should be created.
@@ -116,23 +116,23 @@ export class ListView extends View {
 	 * Note, that the view property of the event data can be pre-initialized with
 	 * an old instance of a view, so that it can be reused.
 	 */
-	on<T extends Observable = Observable>(event: 'itemLoading', callback: (args: ItemEventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = ListView>(event: 'itemLoading', callback: (args: ItemEventData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Raised when an item inside the ListView is tapped.
 	 */
-	on<T extends Observable = Observable>(event: 'itemTap', callback: (args: ItemEventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = ListView>(event: 'itemTap', callback: (args: ItemEventData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Raised when the ListView is scrolled so that its last item is visible.
 	 */
-	on<T extends Observable = Observable>(event: 'loadMoreItems', callback: (args: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = ListView>(event: 'loadMoreItems', callback: (args: EventData<T>) => void, thisArg?: any): void;
 }
 
 /**
  * Event data containing information for the index and the view associated to a list view item.
  */
-export interface ItemEventData<T extends Observable = Observable> extends EventData<T> {
+export interface ItemEventData<T extends Observable = ListView> extends EventData<T> {
 	/**
 	 * The index of the item, for which the event is raised.
 	 */
@@ -164,8 +164,8 @@ export interface TemplatedItemsView {
 	itemTemplate: string | Template;
 	itemTemplates?: string | Array<KeyedTemplate>;
 	refresh(): void;
-	on<T extends Observable = Observable>(event: 'itemLoading', callback: (args: ItemEventData<T>) => void, thisArg?: any): void;
-	off<T extends Observable = Observable>(event: 'itemLoading', callback: (args: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = ListView>(event: 'itemLoading', callback: (args: ItemEventData<T>) => void, thisArg?: any): void;
+	off<T extends Observable = ListView>(event: 'itemLoading', callback: (args: EventData<T>) => void, thisArg?: any): void;
 }
 
 /**
diff --git a/packages/core/ui/list-view/list-view-common.ts b/packages/core/ui/list-view/list-view-common.ts
index 3566d83ad..a1c2a3f48 100644
--- a/packages/core/ui/list-view/list-view-common.ts
+++ b/packages/core/ui/list-view/list-view-common.ts
@@ -154,10 +154,10 @@ export abstract class ListViewBase extends ContainerView implements ListViewDefi
 ListViewBase.prototype.recycleNativeView = 'auto';
 
 export interface ListViewBase {
-	on<T extends Observable = Observable>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
-	on<T extends Observable = Observable>(event: 'itemLoading', callback: (args: ItemEventData<T>) => void, thisArg?: any): void;
-	on<T extends Observable = Observable>(event: 'itemTap', callback: (args: ItemEventData<T>) => void, thisArg?: any): void;
-	on<T extends Observable = Observable>(event: 'loadMoreItems', callback: (args: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = ListViewBase>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = ListViewBase>(event: 'itemLoading', callback: (args: ItemEventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = ListViewBase>(event: 'itemTap', callback: (args: ItemEventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = ListViewBase>(event: 'loadMoreItems', callback: (args: EventData<T>) => void, thisArg?: any): void;
 }
 
 /**
diff --git a/packages/core/ui/page/index.d.ts b/packages/core/ui/page/index.d.ts
index db0ca49c2..7e98ff40e 100644
--- a/packages/core/ui/page/index.d.ts
+++ b/packages/core/ui/page/index.d.ts
@@ -12,7 +12,7 @@ export * from './page-common';
 /**
  * Defines the data for the page navigation events.
  */
-export interface NavigatedData<T extends Observable = Observable> extends EventData<T> {
+export interface NavigatedData<T extends Observable = Page> extends EventData<T> {
 	/**
 	 * The navigation context (optional, may be undefined) passed to the page navigation events method.
 	 */
@@ -116,27 +116,27 @@ export declare class Page extends PageBase {
 	 * @param callback - Callback function which will be executed when event is raised.
 	 * @param thisArg - An optional parameter which will be used as `this` context for callback execution.
 	 */
-	public on<T extends Observable = Observable>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
+	public on<T extends Observable = Page>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Raised when navigation to the page has started.
 	 */
-	public on<T extends Observable = Observable>(event: 'navigatingTo', callback: (args: NavigatedData<T>) => void, thisArg?: any): void;
+	public on<T extends Observable = Page>(event: 'navigatingTo', callback: (args: NavigatedData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Raised when navigation to the page has finished.
 	 */
-	public on<T extends Observable = Observable>(event: 'navigatedTo', callback: (args: NavigatedData<T>) => void, thisArg?: any): void;
+	public on<T extends Observable = Page>(event: 'navigatedTo', callback: (args: NavigatedData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Raised when navigation from the page has started.
 	 */
-	public on<T extends Observable = Observable>(event: 'navigatingFrom', callback: (args: NavigatedData<T>) => void, thisArg?: any): void;
+	public on<T extends Observable = Page>(event: 'navigatingFrom', callback: (args: NavigatedData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Raised when navigation from the page has finished.
 	 */
-	public on<T extends Observable = Observable>(event: 'navigatedFrom', callback: (args: NavigatedData<T>) => void, thisArg?: any): void;
+	public on<T extends Observable = Page>(event: 'navigatedFrom', callback: (args: NavigatedData<T>) => void, thisArg?: any): void;
 	//@private
 
 	/**
diff --git a/packages/core/ui/page/page-common.ts b/packages/core/ui/page/page-common.ts
index 3cff9cb3e..07d9b7bd2 100644
--- a/packages/core/ui/page/page-common.ts
+++ b/packages/core/ui/page/page-common.ts
@@ -12,7 +12,7 @@ import { ActionBar } from '../action-bar';
 import { KeyframeAnimationInfo } from '../animation/keyframe-animation';
 import { profile } from '../../profiling';
 
-interface NavigatedData<T extends Observable = Observable> extends EventData<T> {
+interface NavigatedData<T extends Observable = PageBase> extends EventData<T> {
 	context: any;
 	isBackNavigation: boolean;
 }
@@ -166,13 +166,13 @@ export class PageBase extends ContentView {
 PageBase.prototype.recycleNativeView = 'never';
 
 export interface PageBase {
-	on<T extends Observable = Observable>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
-	on<T extends Observable = Observable>(event: 'navigatingTo', callback: (args: NavigatedData<T>) => void, thisArg?: any): void;
-	on<T extends Observable = Observable>(event: 'navigatedTo', callback: (args: NavigatedData<T>) => void, thisArg?: any): void;
-	on<T extends Observable = Observable>(event: 'navigatingFrom', callback: (args: NavigatedData<T>) => void, thisArg?: any): void;
-	on<T extends Observable = Observable>(event: 'navigatedFrom', callback: (args: NavigatedData<T>) => void, thisArg?: any): void;
-	on<T extends Observable = Observable>(event: 'showingModally', callback: (args: ShownModallyData<T>) => void, thisArg?: any): void;
-	on<T extends Observable = Observable>(event: 'shownModally', callback: (args: ShownModallyData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = PageBase>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = PageBase>(event: 'navigatingTo', callback: (args: NavigatedData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = PageBase>(event: 'navigatedTo', callback: (args: NavigatedData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = PageBase>(event: 'navigatingFrom', callback: (args: NavigatedData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = PageBase>(event: 'navigatedFrom', callback: (args: NavigatedData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = PageBase>(event: 'showingModally', callback: (args: ShownModallyData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = PageBase>(event: 'shownModally', callback: (args: ShownModallyData<T>) => void, thisArg?: any): void;
 }
 
 /**
diff --git a/packages/core/ui/placeholder/index.android.ts b/packages/core/ui/placeholder/index.android.ts
index 35fea8807..52c03a25d 100644
--- a/packages/core/ui/placeholder/index.android.ts
+++ b/packages/core/ui/placeholder/index.android.ts
@@ -21,6 +21,6 @@ export class Placeholder extends View {
 	}
 }
 export interface Placeholder {
-	on<T extends Observable = Observable>(eventNames: string, callback: (args: EventData<T>) => void, thisArg?: any): void;
-	on<T extends Observable = Observable>(event: 'creatingView', callback: (args: CreateViewEventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = Placeholder>(eventNames: string, callback: (args: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = Placeholder>(event: 'creatingView', callback: (args: CreateViewEventData<T>) => void, thisArg?: any): void;
 }
diff --git a/packages/core/ui/placeholder/index.d.ts b/packages/core/ui/placeholder/index.d.ts
index 56bc17580..dba9860ff 100644
--- a/packages/core/ui/placeholder/index.d.ts
+++ b/packages/core/ui/placeholder/index.d.ts
@@ -18,18 +18,18 @@ export class Placeholder extends View {
 	 * @param callback - Callback function which will be executed when event is raised.
 	 * @param thisArg - An optional parameter which will be used as `this` context for callback execution.
 	 */
-	on<T extends Observable = Observable>(eventNames: string, callback: (args: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = Placeholder>(eventNames: string, callback: (args: EventData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Raised when a creatingView event occurs.
 	 */
-	on<T extends Observable = Observable>(event: 'creatingView', callback: (args: CreateViewEventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = Placeholder>(event: 'creatingView', callback: (args: CreateViewEventData<T>) => void, thisArg?: any): void;
 }
 
 /**
  * Event data containing information for creating a native view that will be added to the visual tree.
  */
-export interface CreateViewEventData<T extends Observable = Observable> extends EventData<T> {
+export interface CreateViewEventData<T extends Observable = Placeholder> extends EventData<T> {
 	/**
 	 * The native view that should be added to the visual tree.
 	 */
diff --git a/packages/core/ui/placeholder/index.ts b/packages/core/ui/placeholder/index.ts
index b95b054ea..c32d4bb71 100644
--- a/packages/core/ui/placeholder/index.ts
+++ b/packages/core/ui/placeholder/index.ts
@@ -20,6 +20,6 @@ export class Placeholder extends View {
 	}
 }
 export interface Placeholder {
-	on<T extends Observable = Observable>(eventNames: string, callback: (args: EventData<T>) => void, thisArg?: any): void;
-	on<T extends Observable = Observable>(event: 'creatingView', callback: (args: CreateViewEventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = Placeholder>(eventNames: string, callback: (args: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = Placeholder>(event: 'creatingView', callback: (args: CreateViewEventData<T>) => void, thisArg?: any): void;
 }
diff --git a/packages/core/ui/scroll-view/index.d.ts b/packages/core/ui/scroll-view/index.d.ts
index 530ac716d..b6596f544 100644
--- a/packages/core/ui/scroll-view/index.d.ts
+++ b/packages/core/ui/scroll-view/index.d.ts
@@ -67,17 +67,17 @@ export class ScrollView extends ContentView {
 	 * @param callback - Callback function which will be executed when event is raised.
 	 * @param thisArg - An optional parameter which will be used as `this` context for callback execution.
 	 */
-	on<T extends Observable = Observable>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = ScrollView>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Raised when a scroll event occurs.
 	 */
-	on<T extends Observable = Observable>(event: 'scroll', callback: (args: ScrollEventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = ScrollView>(event: 'scroll', callback: (args: ScrollEventData<T>) => void, thisArg?: any): void;
 
 	_onOrientationChanged(): void;
 }
 
-export interface ScrollEventData<T extends Observable = Observable> extends EventData<T> {
+export interface ScrollEventData<T extends Observable = ScrollView> extends EventData<T> {
 	scrollX: number;
 	scrollY: number;
 }
diff --git a/packages/core/ui/scroll-view/scroll-view-common.ts b/packages/core/ui/scroll-view/scroll-view-common.ts
index f3bb10b29..ac1529620 100644
--- a/packages/core/ui/scroll-view/scroll-view-common.ts
+++ b/packages/core/ui/scroll-view/scroll-view-common.ts
@@ -87,8 +87,8 @@ export abstract class ScrollViewBase extends ContentView implements ScrollViewDe
 	public abstract _onOrientationChanged();
 }
 export interface ScrollViewBase {
-	on<T extends Observable = Observable>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
-	on<T extends Observable = Observable>(event: 'scroll', callback: (args: ScrollEventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = ScrollViewBase>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = ScrollViewBase>(event: 'scroll', callback: (args: ScrollEventData<T>) => void, thisArg?: any): void;
 }
 
 const converter = makeParser<CoreTypes.OrientationType>(makeValidator(CoreTypes.Orientation.horizontal, CoreTypes.Orientation.vertical));
diff --git a/packages/core/ui/search-bar/index.d.ts b/packages/core/ui/search-bar/index.d.ts
index a1de48f76..aeec43410 100644
--- a/packages/core/ui/search-bar/index.d.ts
+++ b/packages/core/ui/search-bar/index.d.ts
@@ -53,17 +53,17 @@ export class SearchBar extends View {
 	 * @param callback - Callback function which will be executed when event is raised.
 	 * @param thisArg - An optional parameter which will be used as `this` context for callback execution.
 	 */
-	on<T extends Observable = Observable>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = SearchBar>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Raised when a search bar search is submitted.
 	 */
-	on<T extends Observable = Observable>(event: 'submit', callback: (args: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = SearchBar>(event: 'submit', callback: (args: EventData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Raised when a search bar search is closed.
 	 */
-	on<T extends Observable = Observable>(event: 'close', callback: (args: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = SearchBar>(event: 'close', callback: (args: EventData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Hides the soft input method, usually a soft keyboard.
diff --git a/packages/core/ui/segmented-bar/index.d.ts b/packages/core/ui/segmented-bar/index.d.ts
index 8553fa305..5b9205732 100644
--- a/packages/core/ui/segmented-bar/index.d.ts
+++ b/packages/core/ui/segmented-bar/index.d.ts
@@ -18,7 +18,7 @@ export class SegmentedBarItem extends ViewBase {
 /**
  * Defines the data for the SegmentedBar.selectedIndexChanged event.
  */
-export interface SelectedIndexChangedEventData<T extends Observable = Observable> extends EventData<T> {
+export interface SelectedIndexChangedEventData<T extends Observable = SegmentedBar> extends EventData<T> {
 	/**
 	 * The old selected index.
 	 */
@@ -60,12 +60,12 @@ export class SegmentedBar extends View implements AddChildFromBuilder, AddArrayF
 	 * @param callback - Callback function which will be executed when event is raised.
 	 * @param thisArg - An optional parameter which will be used as `this` context for callback execution.
 	 */
-	on<T extends Observable = Observable>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = SegmentedBar>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Raised when the selected index changes.
 	 */
-	on<T extends Observable = Observable>(event: 'selectedIndexChanged', callback: (args: SelectedIndexChangedEventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = SegmentedBar>(event: 'selectedIndexChanged', callback: (args: SelectedIndexChangedEventData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Called for every child element declared in xml.
diff --git a/packages/core/ui/slider/index.d.ts b/packages/core/ui/slider/index.d.ts
index b99822c23..65cecd75a 100644
--- a/packages/core/ui/slider/index.d.ts
+++ b/packages/core/ui/slider/index.d.ts
@@ -61,12 +61,12 @@ export const maxValueProperty: CoercibleProperty<Slider, number>;
  */
 export const accessibilityStepProperty: Property<SliderBase, number>;
 
-interface AccessibilityIncrementEventData<T extends Observable = Observable> extends EventData<T> {
+interface AccessibilityIncrementEventData<T extends Observable = Slider> extends EventData<T> {
 	object: Slider;
 	value?: number;
 }
 
-interface AccessibilityDecrementEventData<T extends Observable = Observable> extends EventData<T> {
+interface AccessibilityDecrementEventData<T extends Observable = Slider> extends EventData<T> {
 	object: Slider;
 	value?: number;
 }
diff --git a/packages/core/ui/tab-view/index.d.ts b/packages/core/ui/tab-view/index.d.ts
index d57989ee4..56918da23 100644
--- a/packages/core/ui/tab-view/index.d.ts
+++ b/packages/core/ui/tab-view/index.d.ts
@@ -42,7 +42,7 @@ export class TabViewItem extends ViewBase {
 /**
  * Defines the data for the TabView.selectedIndexChanged event.
  */
-export interface SelectedIndexChangedEventData<T extends Observable = Observable> extends EventData<T> {
+export interface SelectedIndexChangedEventData<T extends Observable = TabView> extends EventData<T> {
 	/**
 	 * The old selected index.
 	 */
@@ -150,12 +150,12 @@ export class TabView extends View {
 	 * @param callback - Callback function which will be executed when event is raised.
 	 * @param thisArg - An optional parameter which will be used as `this` context for callback execution.
 	 */
-	on<T extends Observable = Observable>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = TabView>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Raised when the selected index changes.
 	 */
-	on<T extends Observable = Observable>(event: 'selectedIndexChanged', callback: (args: SelectedIndexChangedEventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = TabView>(event: 'selectedIndexChanged', callback: (args: SelectedIndexChangedEventData<T>) => void, thisArg?: any): void;
 }
 
 export const itemsProperty: Property<TabView, TabViewItem[]>;
diff --git a/packages/core/ui/tab-view/tab-view-common.ts b/packages/core/ui/tab-view/tab-view-common.ts
index d07c4b8db..969f85f80 100644
--- a/packages/core/ui/tab-view/tab-view-common.ts
+++ b/packages/core/ui/tab-view/tab-view-common.ts
@@ -205,8 +205,8 @@ export class TabViewBase extends View implements TabViewDefinition, AddChildFrom
 }
 
 export interface TabViewBase {
-	on<T extends Observable = Observable>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
-	on<T extends Observable = Observable>(event: 'selectedIndexChanged', callback: (args: SelectedIndexChangedEventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = TabViewBase>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = TabViewBase>(event: 'selectedIndexChanged', callback: (args: SelectedIndexChangedEventData<T>) => void, thisArg?: any): void;
 }
 
 export function traceMissingIcon(icon: string) {
diff --git a/packages/core/ui/text-base/span.ts b/packages/core/ui/text-base/span.ts
index 9cf29d1c8..843855960 100644
--- a/packages/core/ui/text-base/span.ts
+++ b/packages/core/ui/text-base/span.ts
@@ -81,12 +81,12 @@ export class Span extends ViewBase implements SpanDefinition {
 		return this._tappable;
 	}
 
-	addEventListener<T extends Observable = Observable>(arg: string, callback: (data: EventData<T>) => void, thisArg?: any): void {
+	addEventListener<T extends Observable = Span>(arg: string, callback: (data: EventData<T>) => void, thisArg?: any): void {
 		super.addEventListener(arg, callback, thisArg);
 		this._setTappable(this.hasListeners(Span.linkTapEvent));
 	}
 
-	removeEventListener<T extends Observable = Observable>(arg: string, callback?: (data: EventData<T>) => void, thisArg?: any): void {
+	removeEventListener<T extends Observable = Span>(arg: string, callback?: (data: EventData<T>) => void, thisArg?: any): void {
 		super.removeEventListener(arg, callback, thisArg);
 		this._setTappable(this.hasListeners(Span.linkTapEvent));
 	}
diff --git a/packages/core/ui/web-view/index.d.ts b/packages/core/ui/web-view/index.d.ts
index 9f2160ad3..1a8097ead 100644
--- a/packages/core/ui/web-view/index.d.ts
+++ b/packages/core/ui/web-view/index.d.ts
@@ -92,23 +92,23 @@ export class WebView extends View {
 	 * @param callback - Callback function which will be executed when event is raised.
 	 * @param thisArg - An optional parameter which will be used as `this` context for callback execution.
 	 */
-	on<T extends Observable = Observable>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = WebView>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Raised when a loadFinished event occurs.
 	 */
-	on<T extends Observable = Observable>(event: 'loadFinished', callback: (args: LoadEventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = WebView>(event: 'loadFinished', callback: (args: LoadEventData<T>) => void, thisArg?: any): void;
 
 	/**
 	 * Raised when a loadStarted event occurs.
 	 */
-	on<T extends Observable = Observable>(event: 'loadStarted', callback: (args: LoadEventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = WebView>(event: 'loadStarted', callback: (args: LoadEventData<T>) => void, thisArg?: any): void;
 }
 
 /**
  * Event data containing information for the loading events of a WebView.
  */
-export interface LoadEventData<T extends Observable = Observable> extends EventData<T> {
+export interface LoadEventData<T extends Observable = WebView> extends EventData<T> {
 	/**
 	 * Gets the url of the web-view.
 	 */
diff --git a/packages/core/ui/web-view/web-view-common.ts b/packages/core/ui/web-view/web-view-common.ts
index 1cf67287d..6c276f5dd 100644
--- a/packages/core/ui/web-view/web-view-common.ts
+++ b/packages/core/ui/web-view/web-view-common.ts
@@ -29,7 +29,7 @@ export abstract class WebViewBase extends ContainerView {
 			error: error,
 		};
 
-		this.notify(<any>args);
+		this.notify(args);
 	}
 
 	public _onLoadStarted(url: string, navigationType: WebViewNavigationType) {
@@ -41,7 +41,7 @@ export abstract class WebViewBase extends ContainerView {
 			error: undefined,
 		};
 
-		this.notify(<any>args);
+		this.notify(args);
 	}
 
 	abstract _loadUrl(src: string): void;
@@ -101,9 +101,9 @@ export abstract class WebViewBase extends ContainerView {
 // HACK: We declare all these 'on' statements, so that they can appear in the API reference
 // HACK: Do we need this? Is it useful? There are static fields to the WebViewBase class for the event names.
 export interface WebViewBase {
-	on<T extends Observable = Observable>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
-	on<T extends Observable = Observable>(event: 'loadFinished', callback: (args: LoadEventData<T>) => void, thisArg?: any): void;
-	on<T extends Observable = Observable>(event: 'loadStarted', callback: (args: LoadEventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = WebViewBase>(eventNames: string, callback: (data: EventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = WebViewBase>(event: 'loadFinished', callback: (args: LoadEventData<T>) => void, thisArg?: any): void;
+	on<T extends Observable = WebViewBase>(event: 'loadStarted', callback: (args: LoadEventData<T>) => void, thisArg?: any): void;
 }
 
 srcProperty.register(WebViewBase);
diff --git a/packages/core/ui/web-view/web-view-interfaces.ts b/packages/core/ui/web-view/web-view-interfaces.ts
index 8b43a5800..3d14164b6 100644
--- a/packages/core/ui/web-view/web-view-interfaces.ts
+++ b/packages/core/ui/web-view/web-view-interfaces.ts
@@ -1,9 +1,10 @@
-import { WebView } from '.';
+import { WebViewBase } from './web-view-common';
+import { WebView } from '.';
 import { EventData, Observable } from '../../data/observable';
 
 export type WebViewNavigationType = 'linkClicked' | 'formSubmitted' | 'backForward' | 'reload' | 'formResubmitted' | 'other' | undefined;
 
-export interface LoadEventData<T extends Observable = Observable> extends EventData<T> {
+export interface LoadEventData<T extends Observable = WebViewBase> extends EventData<T> {
 	url: string;
 	navigationType: WebViewNavigationType;
 	error: string;