fix(Application): inBackground handling & missing once (#10307)

packages/core/application/application-common.ts

@@ -128,6 +128,7 @@ export class ApplicationCommon {
 
 	// Application events go through the global events.
 	on: ApplicationEvents['on'] = globalEvents.on.bind(globalEvents);
+	once: ApplicationEvents['on'] = globalEvents.once.bind(globalEvents);
 	off: ApplicationEvents['off'] = globalEvents.off.bind(globalEvents);
 	notify: ApplicationEvents['notify'] = globalEvents.notify.bind(globalEvents);
 	hasListeners: ApplicationEvents['hasListeners'] = globalEvents.hasListeners.bind(globalEvents);

packages/core/application/application.android.ts

@@ -138,11 +138,11 @@ class NativeScriptLifecycleCallbacks extends android.app.Application.ActivityLif
 
 		this.activitiesCount++;
 		if (this.activitiesCount === 1) {
-			Application.android.notify({
-				eventName: Application.foregroundEvent,
-				object: Application.android,
+			Application.android.setInBackground(false, {
+				// todo: deprecate event.android in favor of event.activity
 				android: activity,
-			} as ApplicationEventData);
+				activity,
+			});
 		}
 
 		Application.android.notify({
@@ -157,11 +157,11 @@ class NativeScriptLifecycleCallbacks extends android.app.Application.ActivityLif
 		// console.log('NativeScriptLifecycleCallbacks onActivityStopped');
 		this.activitiesCount--;
 		if (this.activitiesCount === 0) {
-			Application.android.notify({
-				eventName: Application.backgroundEvent,
-				object: Application.android,
+			Application.android.setInBackground(true, {
+				// todo: deprecate event.android in favor of event.activity
 				android: activity,
-			} as ApplicationEventData);
+				activity,
+			});
 		}
 
 		Application.android.notify({

packages/core/jest.setup.ts

@@ -98,6 +98,7 @@ global.CFRunLoopWakeUp = function (runloop) {};
 global.NativeScriptGlobals = {
 	events: {
 		on: (args) => {},
+		once: (args) => {},
 		off: (args) => {},
 		notify: (args) => {},
 		hasListeners: (args) => {},