Add 'displayed' event for android, close to the Displayed point logged in the android monitor for activity startup

tns-core-modules/application/application-common.ts

@@ -21,6 +21,7 @@ import { UnhandledErrorEventData, iOSApplication, AndroidApplication, CssChanged
 
 export const launchEvent = "launch";
 export const suspendEvent = "suspend";
+export const displayedEvent = "displayed";
 export const resumeEvent = "resume";
 export const exitEvent = "exit";
 export const lowMemoryEvent = "lowMemory";
@@ -45,6 +46,7 @@ export let ios = undefined;
 export const on: typeof events.on = events.on.bind(events);
 export const off: typeof events.off = events.off.bind(events);
 export const notify: typeof events.notify = events.notify.bind(events);
+export const hasListeners: typeof events.hasListeners = events.hasListeners.bind(events);
 
 let app: iOSApplication | AndroidApplication;
 export function setApplication(instance: iOSApplication | AndroidApplication): void {

tns-core-modules/application/application.android.ts

@@ -4,7 +4,7 @@
 } from ".";
 
 import {
-    notify, lowMemoryEvent, orientationChangedEvent, suspendEvent, resumeEvent,
+    notify, hasListeners, lowMemoryEvent, orientationChangedEvent, suspendEvent, resumeEvent, displayedEvent,
     setApplication, livesync, Observable
 } from "./application-common";
 
@@ -181,7 +181,19 @@ function initLifecycleCallbacks() {
                 androidApp.startActivity = activity;
             }
 
-            androidApp.notify(<AndroidActivityBundleEventData>{ eventName: ActivityCreated, object: androidApp, activity: activity, bundle: savedInstanceState });
+            androidApp.notify(<AndroidActivityBundleEventData>{ eventName: ActivityCreated, object: androidApp, activity, bundle: savedInstanceState });
+
+            if (hasListeners(displayedEvent)) {
+                let rootView = activity.findViewById((<any>android).R.id.content);
+                let onGlobalLayoutListener = new android.view.ViewTreeObserver.OnGlobalLayoutListener({
+                    onGlobalLayout() {
+                        notify({ eventName: displayedEvent, object: androidApp, activity });
+                        let viewTreeObserver = rootView.getViewTreeObserver();
+                        viewTreeObserver.removeOnGlobalLayoutListener(onGlobalLayoutListener);
+                    }
+                });
+                rootView.getViewTreeObserver().addOnGlobalLayoutListener(onGlobalLayoutListener);
+            }
         },
 
         onActivityDestroyed: function (activity: android.app.Activity) {

tns-core-modules/application/application.d.ts

@@ -11,6 +11,11 @@ import { NavigationEntry, View, Observable, EventData } from "../ui/frame";
  */
 export var launchEvent: string;
 
+/**
+ * String value used when hooking to displayed event.
+ */
+export var displayedEvent: string;
+
 /**
  * String value used when hooking to uncaughtError event.
  */
@@ -189,6 +194,11 @@ export function hasListeners(eventName: string): boolean;
  */
 export function on(event: "launch", callback: (args: LaunchEventData) => void, thisArg?: any);
 
+/**
+ * This event is raised after the application has launched and was fully drawn.
+ */
+export function on(event: "displayed", callback: (args: EventData) => void, thisArg?: any);
+
 /**
  * This event is raised when the Application is suspended.
  */