fix: nested fragments interact thru child fragment manager (#6293)

tests/app/ui/tab-view/tab-view-root-tests.ts

@@ -1,13 +1,12 @@
-import * as helper from "../helper";
 import TKUnit = require("../../TKUnit");
-import { isIOS, isAndroid } from "tns-core-modules/platform";
+import { isAndroid } from "tns-core-modules/platform";
 import { _resetRootView } from "tns-core-modules/application/";
 import { Frame, NavigationEntry, topmost } from "tns-core-modules/ui/frame";
 import { Page } from "tns-core-modules/ui/page";
 import { TabView, TabViewItem } from "tns-core-modules/ui/tab-view";
 
 function waitUntilNavigatedToMaxTimeout(pages: Page[], action: Function) {
-    const maxTimeout = 5;
+    const maxTimeout = 8;
     let completed = 0;
     function navigatedTo(args) {
         args.object.page.off("navigatedTo", navigatedTo);
@@ -67,14 +66,20 @@ export function test_frame_topmost_matches_selectedIndex() {
         create: () => tabView
     };
 
-    waitUntilNavigatedToMaxTimeout([items[0].page], () => _resetRootView(entry));
+    if (isAndroid) {
+        waitUntilNavigatedToMaxTimeout([items[0].page, items[1].page], () => _resetRootView(entry));
+        TKUnit.assertEqual(topmost().id, "Tab0 Frame0");
     
+        tabView.selectedIndex = 1;
+        TKUnit.assertEqual(topmost().id, "Tab1 Frame1");
+    } else {
+        waitUntilNavigatedToMaxTimeout([items[0].page], () => _resetRootView(entry));
         TKUnit.assertEqual(topmost().id, "Tab0 Frame0");
 
         waitUntilNavigatedToMaxTimeout([items[1].page], () => tabView.selectedIndex = 1);
-
         TKUnit.assertEqual(topmost().id, "Tab1 Frame1");
     }
+}
 
 export function test_offset_zero_should_raise_same_events() {
     let actualEventsRaised = [];

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

@@ -234,6 +234,7 @@ export class View extends ViewCommon {
     private layoutChangeListenerIsSet: boolean;
     private layoutChangeListener: android.view.View.OnLayoutChangeListener;
     private _manager: android.support.v4.app.FragmentManager;
+    private _rootManager: android.support.v4.app.FragmentManager;
 
     nativeViewProtected: android.view.View;
 
@@ -265,21 +266,53 @@ export class View extends ViewCommon {
         }
     }
 
+    public _getChildFragmentManager(): android.support.v4.app.FragmentManager {
+        return null;
+    }
+
+    public _getRootFragmentManager(): android.support.v4.app.FragmentManager {
+        if (!this._rootManager && this._context) {
+            this._rootManager = (<android.support.v4.app.FragmentActivity>this._context).getSupportFragmentManager();
+        }
+
+        return this._rootManager;
+    }
+
     public _getFragmentManager(): android.support.v4.app.FragmentManager {
         let manager = this._manager;
         if (!manager) {
             let view: View = this;
+            let frameOrTabViewItemFound = false;
             while (view) {
+                // when interacting with nested fragments instead of using getSupportFragmentManager 
+                // we must always use getChildFragmentManager instead;
+                // we have three sources of fragments -- Frame fragments, TabViewItem fragments, and
+                // modal dialog fragments
+
+                // modal -> frame / tabview (frame / tabview use modal CHILD fm)
                 const dialogFragment = view._dialogFragment;
                 if (dialogFragment) {
                     manager = dialogFragment.getChildFragmentManager();
                     break;
-                } else {
+                }
+
+                // - frame1 -> frame2 (frame2 uses frame1 CHILD fm)
+                // - tabview -> frame1 (frame1 uses tabview item CHILD fm)
+                // - frame1 -> tabview (tabview uses frame1 CHILD fm)
+                // - frame1 -> tabview -> frame2 (tabview uses frame1 CHILD fm; frame2 uses tabview item CHILD fm)
+                if (view._hasFragments) {
+                    if (frameOrTabViewItemFound) {
+                        manager = view._getChildFragmentManager();
+                        break;
+                    }
+
+                    frameOrTabViewItemFound = true;
+                }
+
                 // the case is needed because _dialogFragment is on View
                 // but parent may be ViewBase.
                 view = view.parent as View;
             }
-            }
 
             if (!manager && this._context) {
                 manager = (<android.support.v4.app.FragmentActivity>this._context).getSupportFragmentManager();
@@ -294,6 +327,7 @@ export class View extends ViewCommon {
     @profile
     public onLoaded() {
         this._manager = null;
+        this._rootManager = null;
         super.onLoaded();
         this.setOnTouchListener();
     }
@@ -307,6 +341,7 @@ export class View extends ViewCommon {
         }
 
         this._manager = null;
+        this._rootManager = null;
         super.onUnloaded();
     }
 
@@ -405,6 +440,10 @@ export class View extends ViewCommon {
         return false;
     }
 
+    get _hasFragments(): boolean {
+        return false;
+    }
+
     public layoutNativeView(left: number, top: number, right: number, bottom: number): void {
         if (this.nativeViewProtected) {
             this.nativeViewProtected.layout(left, top, right, bottom);
@@ -571,7 +610,7 @@ export class View extends ViewCommon {
         this._dialogFragment = df;
         this._raiseShowingModallyEvent();
 
-        this._dialogFragment.show(parent._getFragmentManager(), this._domId.toString());
+        this._dialogFragment.show(parent._getRootFragmentManager(), this._domId.toString());
     }
 
     protected _hideNativeModalView(parent: View) {

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

@@ -121,6 +121,10 @@ export class Frame extends FrameBase {
         return this._android;
     }
 
+    get _hasFragments(): boolean {
+        return true;
+    }
+
     _onAttachedToWindow(): void {
         super._onAttachedToWindow();
         this._attachedToWindow = true;
@@ -175,7 +179,16 @@ export class Frame extends FrameBase {
         }
     }
 
-    _onRootViewReset(): void {
+    public _getChildFragmentManager() {
+        const backstackEntry = this._executingEntry || this._currentEntry;
+        if (backstackEntry && backstackEntry.fragment && backstackEntry.fragment.isAdded()) {
+            return backstackEntry.fragment.getChildFragmentManager();
+        }
+
+        return null;
+    }
+
+    public _onRootViewReset(): void {
         this.disposeCurrentFragment();
         super._onRootViewReset();
     }
@@ -186,7 +199,14 @@ export class Frame extends FrameBase {
     }
 
     private disposeCurrentFragment(): void {
-        if (!this._currentEntry || !this._currentEntry.fragment) {
+        // when interacting with nested fragments it seems Android is smart enough
+        // to automatically remove child fragments when parent fragment is removed;
+        // however, we must add a fragment.isAdded() guard as our logic will try to 
+        // explicitly remove the already removed child fragment causing an 
+        // IllegalStateException: Fragment has not been attached yet.
+        if (!this._currentEntry || 
+            !this._currentEntry.fragment || 
+            !this._currentEntry.fragment.isAdded()) {
             return;
         }
 

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

@@ -125,6 +125,10 @@ export class Frame extends View {
      * @private
      */
     _currentEntry: BackstackEntry;
+    /**
+     * @private
+     */
+    _executingEntry: BackstackEntry;
     /**
      * @private
      */

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

@@ -260,6 +260,10 @@ export class TabViewItem extends TabViewItemBase {
     public index: number;
     private _defaultTransformationMethod: android.text.method.TransformationMethod;
 
+    get _hasFragments(): boolean {
+        return true;
+    }
+
     public initNativeView(): void {
         super.initNativeView();
         if (this.nativeViewProtected) {
@@ -297,6 +301,24 @@ export class TabViewItem extends TabViewItemBase {
         }
     }
 
+    public _getChildFragmentManager(): android.support.v4.app.FragmentManager {
+        const tabView = this.parent as TabView;
+        let tabFragment = null;
+        const fragmentManager = tabView._getFragmentManager();
+        for (let fragment of (<Array<any>>fragmentManager.getFragments().toArray())) {
+            if (fragment.index === this.index) {
+                tabFragment = fragment;
+                break;
+            }
+        }
+
+        if (!tabFragment) {
+            throw new Error(`Could not get child fragment manager for tab item with index ${this.index}`);
+        }
+
+        return tabFragment.getChildFragmentManager();
+    }
+
     [fontSizeProperty.getDefault](): { nativeSize: number } {
         return { nativeSize: this.nativeViewProtected.getTextSize() };
     }
@@ -361,6 +383,10 @@ export class TabView extends TabViewBase {
         tabs.push(new WeakRef(this));
     }
 
+    get _hasFragments(): boolean {
+        return true;
+    }
+
     public onItemsChanged(oldItems: TabViewItem[], newItems: TabViewItem[]): void {
         super.onItemsChanged(oldItems, newItems);
 
@@ -512,6 +538,20 @@ export class TabView extends TabViewBase {
         return false;
     }
 
+    public _onRootViewReset(): void {
+        this.disposeCurrentFragments();
+        super._onRootViewReset();
+    }
+
+    private disposeCurrentFragments(): void {
+        const fragmentManager = this._getFragmentManager();
+        const transaction = fragmentManager.beginTransaction();
+        for (let fragment of (<Array<any>>fragmentManager.getFragments().toArray())) {
+            transaction.remove(fragment);
+        }
+        transaction.commitNowAllowingStateLoss();
+    }
+
     private shouldUpdateAdapter(items: Array<TabViewItemDefinition>) {
         if (!this._pagerAdapter) {
             return false;