fix(init): Bootstrap Angular on page "navigatingTo" event.

Avoid a brief flash of a blank page on slower devices.

Author: hdeshev

Diff for: nativescript-angular/platform-common.ts

@@ -61,11 +61,20 @@ export const COMMON_PROVIDERS = [
 
 export class NativeScriptPlatformRef extends PlatformRef {
     private _bootstrapper: BootstrapperAction;
+    private static _rootPageRef: WeakRef<Page>;
 
     constructor(private platform: PlatformRef, private appOptions?: AppOptions) {
         super();
     }
 
+    static set rootPage(page: Page) {
+        NativeScriptPlatformRef._rootPageRef = new WeakRef(page);
+    }
+
+    static get rootPage(): Page {
+        return NativeScriptPlatformRef._rootPageRef.get();
+    }
+
     bootstrapModuleFactory<M>(moduleFactory: NgModuleFactory<M>): Promise<NgModuleRef<M>> {
         this._bootstrapper = () => this.platform.bootstrapModuleFactory(moduleFactory);
 
@@ -149,12 +158,13 @@ export class NativeScriptPlatformRef extends PlatformRef {
         const navEntry: NavigationEntry = {
             create: (): Page => {
                 let page = pageFactory({ isBootstrap: true, isLivesync });
+                NativeScriptPlatformRef.rootPage = page;
                 if (this.appOptions) {
                     page.actionBarHidden = this.appOptions.startPageActionBarHidden;
                 }
 
-                let onLoadedHandler = function () {
-                    page.off("loaded", onLoadedHandler);
+                let initHandler = function () {
+                    page.off(Page.navigatingToEvent, initHandler);
                     // profiling.stop("application-start");
                     rendererLog("Page loaded");
 
@@ -184,7 +194,7 @@ export class NativeScriptPlatformRef extends PlatformRef {
                     });
                 };
 
-                page.on("loaded", onLoadedHandler);
+                page.on(Page.navigatingToEvent, initHandler);
 
                 return page;
             }

Diff for: nativescript-angular/renderer.ts

@@ -14,6 +14,7 @@ import { NgView } from "./element-registry";
 import { rendererLog as traceLog } from "./trace";
 import { escapeRegexSymbols } from "tns-core-modules/utils/utils";
 import { Device } from "tns-core-modules/platform";
+import { NativeScriptPlatformRef } from "./platform-common";
 
 import { NativeScriptAnimationDriver } from "./animation-driver";
 
@@ -46,7 +47,7 @@ export class NativeScriptRootRenderer implements RootRenderer {
 
     public get rootView(): View {
         if (!this._rootView) {
-            this._rootView = topmost().currentPage;
+            this._rootView = NativeScriptPlatformRef.rootPage || topmost().currentPage;
         }
         return this._rootView;
     }