feat: Add methods to get the root view and set a different root view at run time (#5386)

* feat: add option to set a different root view at run time

* feat: expose application getRootView method

* refactor: Introduce ViewEntry interface

* fix: Respect root view rturned from launch event in Android

* refactor: getRootView() code + caching root view per activity.

* refactor: add app-root.xml in apps

* refactor: http test made async

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

@@ -2,6 +2,8 @@
 require("globals");
 
 import { Observable, EventData } from "../data/observable";
+// types
+import { View } from "../ui/core/view";
 import {
     trace as profilingTrace,
     time,

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

@@ -13,7 +13,8 @@ import { profile } from "../profiling";
 // First reexport so that app module is initialized.
 export * from "./application-common";
 
-import { NavigationEntry } from "../ui/frame";
+// types
+import { NavigationEntry, View, AndroidActivityCallbacks } from "../ui/frame";
 
 const ActivityCreated = "activityCreated";
 const ActivityDestroyed = "activityDestroyed";
@@ -53,7 +54,7 @@ export class AndroidApplication extends Observable implements AndroidApplication
         if (this.nativeApp === nativeApp) {
             return;
         }
-        
+
         if (this.nativeApp) {
             throw new Error("application.android already initialized.");
         }
@@ -148,10 +149,35 @@ export function run(entry?: NavigationEntry | string) {
     start(entry);
 }
 
+const CALLBACKS = "_callbacks";
+
+export function _resetRootView(entry?: NavigationEntry | string) {
+    const activity = androidApp.foregroundActivity;
+    if (!activity) {
+        throw new Error("Cannot find android activity.");
+    }
+
+    mainEntry = typeof entry === "string" ? { moduleName: entry } : entry;
+    const callbacks: AndroidActivityCallbacks = activity[CALLBACKS];
+    callbacks.resetActivityContent(activity);
+}
+
 export function getMainEntry() {
     return mainEntry;
 }
 
+export function getRootView() {
+    // Use start activity as a backup when foregroundActivity is still not set
+    // in cases when we are getting the root view before activity.onResumed event is fired
+    const activity = androidApp.foregroundActivity || androidApp.startActivity;
+    if (!activity) {
+        return undefined;
+    }
+    const callbacks: AndroidActivityCallbacks = activity[CALLBACKS];
+
+    return callbacks ? callbacks.getRootView() : undefined;
+}
+
 export function getNativeApplication(): android.app.Application {
     // Try getting it from module - check whether application.android.init has been explicitly called
     let nativeApp = androidApp.nativeApp;
@@ -202,11 +228,11 @@ function initLifecycleCallbacks() {
         }
     });
 
-    const notifyActivityCreated = profile("notifyActivityCreated", function(activity: android.app.Activity, savedInstanceState: android.os.Bundle) {
+    const notifyActivityCreated = profile("notifyActivityCreated", function (activity: android.app.Activity, savedInstanceState: android.os.Bundle) {
         androidApp.notify(<AndroidActivityBundleEventData>{ eventName: ActivityCreated, object: androidApp, activity, bundle: savedInstanceState });
     });
 
-    const subscribeForGlobalLayout = profile("subscribeForGlobalLayout", function(activity: android.app.Activity) {
+    const subscribeForGlobalLayout = profile("subscribeForGlobalLayout", function (activity: android.app.Activity) {
         const rootView = activity.getWindow().getDecorView().getRootView();
         let onGlobalLayoutListener = new android.view.ViewTreeObserver.OnGlobalLayoutListener({
             onGlobalLayout() {

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

@@ -116,6 +116,11 @@ export interface CssChangedEventData extends EventData {
  */
 export function getMainEntry(): NavigationEntry;
 
+/**
+ * Get current application root view.
+ */
+export function getRootView(): View;
+
 /**
  * Get application level static resources.
  */
@@ -178,6 +183,12 @@ export function start(entry?: NavigationEntry | string);
  */
 export function run(entry?: NavigationEntry | string);
 
+/**
+ * Call this method to change the root view of your application. Important: Your application must already be running.
+ * This method won't create Frame as root view.
+ */
+export function _resetRootView(entry?: NavigationEntry | string);
+
 //@private
 /**
  * Internal method use to check if a root Frame should be automatically created as root view.

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

@@ -100,6 +100,10 @@ class IOSApplication implements IOSApplicationDefinition {
         }
     }
 
+    get rootView() : View {
+        return this._rootView;
+    }
+
     public addNotificationObserver(notificationName: string, onReceiveCallback: (notification: NSNotification) => void): NotificationObserver {
         const observer = NotificationObserver.initWithCallback(onReceiveCallback);
         utils.ios.getter(NSNotificationCenter, NSNotificationCenter.defaultCenter).addObserverSelectorNameObject(observer, "onReceive", notificationName, null);
@@ -263,6 +267,10 @@ export function getMainEntry() {
     return mainEntry;
 }
 
+export function getRootView() {
+    return iosApp.rootView;
+}
+
 // NOTE: for backwards compatibility. Remove for 4.0.0.
 let createRootFrame = true;
 let started: boolean = false;
@@ -296,6 +304,12 @@ export function run(entry?: string | NavigationEntry) {
     start(entry);
 }
 
+export function _resetRootView(entry?: NavigationEntry | string) {
+    createRootFrame = false;
+    mainEntry = typeof entry === "string" ? { moduleName: entry } : entry;
+    iosApp.setWindowContent();
+}
+
 export function getNativeApplication(): UIApplication {
     return iosApp.nativeApp;
 }