fix-next: ensure proper events on tab change (#5468)

tns-core-modules/ui/frame/frame.android.ts

@@ -201,9 +201,7 @@ export class Frame extends FrameBase {
         const currentEntryChanged = current !== entry;
         if (currentEntryChanged) {
             this._updateBackstack(entry, isBack);
-        }
 
-        if (currentEntryChanged) {
             // If activity was destroyed we need to destroy fragment and UI
             // of current and new entries.
             if (this._tearDownPending) {
@@ -936,7 +934,9 @@ class ActivityCallbacksImplementation implements AndroidActivityCallbacks {
 
     public resetActivityContent(activity: android.app.Activity): void {
         if (this._rootView) {
-            // if we already have a root view, we reset it.
+            const manager = this._rootView._getFragmentManager();
+            manager.executePendingTransactions();
+
             this._rootView._onRootViewReset();
         }
         // Delete previously cached root view in order to recreate it.

tns-core-modules/ui/frame/frame.ios.ts

@@ -38,11 +38,13 @@ export class Frame extends FrameBase {
     }
 
     public setCurrent(entry: BackstackEntry, isBack: boolean): void {
-        if (entry !== this._currentEntry) {
+        const current = this._currentEntry;
+        const currentEntryChanged = current !== entry;
+        if (currentEntryChanged) {
             this._updateBackstack(entry, isBack);
-        }
 
-        super.setCurrent(entry, isBack);
+            super.setCurrent(entry, isBack);
+        }
     }
 
     @profile

tns-core-modules/ui/tab-view/tab-view.ios.ts

@@ -32,7 +32,7 @@ class UITabBarControllerImpl extends UITabBarController {
     public viewWillAppear(animated: boolean): void {
         super.viewWillAppear(animated);
         const owner = this._owner.get();
-        if(!owner){
+        if (!owner) {
             return;
         }
 
@@ -147,7 +147,7 @@ function updateItemIconPosition(tabBarItem: UITabBarItem): void {
 
 export class TabViewItem extends TabViewItemBase {
     private __controller: UIViewController;
-    
+
     public setViewController(controller: UIViewController, nativeView: UIView) {
         this.__controller = controller;
         this.setNativeView(nativeView);
@@ -295,7 +295,7 @@ export class TabView extends TabViewBase {
 
     private getViewController(item: TabViewItem): UIViewController {
         let newController: UIViewController = item.view ? item.view.viewController : null;
-        
+
         if (newController) {
             item.setViewController(newController, newController.view);
             return newController;
@@ -399,6 +399,7 @@ export class TabView extends TabViewBase {
         }
 
         if (value > -1) {
+            (<any>this._ios)._willSelectViewController = this._ios.viewControllers[value];
             this._ios.selectedIndex = value;
         }
     }