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

@@ -3,16 +3,19 @@ import {
     Renderer2, RendererFactory2, RendererType2,
     RendererStyleFlags2, ViewEncapsulation,
 } from "@angular/core";
-import { APP_ROOT_VIEW, DEVICE } from "./platform-providers";
+
 import { isBlank } from "./lang-facade";
 import { View } from "ui/core/view";
 import { addCss } from "application";
 import { topmost } from "ui/frame";
+import { escapeRegexSymbols } from "utils/utils";
+import { Device } from "platform";
+
 import { ViewUtil } from "./view-util";
+import { APP_ROOT_VIEW, DEVICE } from "./platform-providers";
 import { NgView } from "./element-registry";
 import { rendererLog as traceLog } from "./trace";
-import { escapeRegexSymbols } from "utils/utils";
-import { Device } from "platform";
+import { NativeScriptPlatformRef } from "./platform-common";
 
 // CONTENT_ATTR not exported from NativeScript_renderer - we need it for styles application.
 const COMPONENT_REGEX = /%COMP%/g;
@@ -41,7 +44,7 @@ export class NativeScriptRendererFactory implements RendererFactory2 {
 
     private setRootNgView(rootView: any) {
         if (!rootView) {
-            rootView = <NgView><any>topmost().currentPage;
+            rootView = NativeScriptPlatformRef.rootPage || <NgView><any>topmost().currentPage;
         }
         rootView.nodeName = "NONE";
         this.rootNgView = rootView;