fix: trying to fix errors with bottom navigation and tabs

Author: farfromrefug

src/bottom-navigation/index.android.ts

@@ -397,6 +397,7 @@ export class BottomNavigation extends TabNavigationBase {
 
     _onAttachedToWindow(): void {
         super._onAttachedToWindow();
+        console.log('_onAttachedToWindow', new Error().stack)
 
         // _onAttachedToWindow called from OS again after it was detach
         // TODO: Consider testing and removing it when update to androidx.fragment:1.2.0
@@ -410,7 +411,7 @@ export class BottomNavigation extends TabNavigationBase {
 
     _onDetachedFromWindow(): void {
         super._onDetachedFromWindow();
-
+        this.disposeTabFragments();
         this._attachedToWindow = false;
     }
 
@@ -448,11 +449,16 @@ export class BottomNavigation extends TabNavigationBase {
     }
 
     private disposeTabFragments(): void {
+        console.log('disposeTabFragsments');
         const fragments = this.fragments;
         for (let i = 0; i < fragments.length; i++) {
             this.removeFragment(fragments[i]);
         }
-        this._currentFragment = null;
+        // const items = this.items;
+        // items.forEach((item, i) => {
+        //     item.unloadView(item.content);
+        // });
+        // this._currentFragment = null;
         this.fragments = [];
     }
     private attachFragment(fragment: androidx.fragment.app.Fragment, id?: number, name?: string): void {
@@ -493,7 +499,7 @@ export class BottomNavigation extends TabNavigationBase {
     public changeTab(index: number) {
         // index is -1 when there are no items
         // bot nav is not attached if you change the tab too early
-        if (index === -1 || (this._currentFragment && index === this.selectedIndex) || !this._attachedToWindow) {
+        if (index === -1 || !this._attachedToWindow) {
             return;
         }
 
@@ -522,21 +528,23 @@ export class BottomNavigation extends TabNavigationBase {
             this.attachFragment(fragment, container.getId(), name);
         }
 
-        if (fragment !== this._currentFragment) {
-            fragment.setMenuVisibility(false);
-            fragment.setUserVisibleHint(false);
-        }
+        // if (fragment !== this._currentFragment) {
+        //     fragment.setMenuVisibility(false);
+        //     fragment.setUserVisibleHint(false);
+        // }
 
         return fragment;
     }
 
     private setPrimaryItem(position: number, fragment: androidx.fragment.app.Fragment, force = false): void {
         if (fragment !== this._currentFragment || force) {
             if (this._currentFragment != null) {
+                console.log('setPrimaryItem hiding curret', this.selectedIndex,this._currentFragment);
                 this._currentFragment.setMenuVisibility(false);
                 this._currentFragment.setUserVisibleHint(false);
             }
 
+            console.log('setPrimaryItem', position,fragment);
             if (fragment != null) {
                 fragment.setMenuVisibility(true);
                 fragment.setUserVisibleHint(true);

src/tabs/tabs.android.ts

@@ -1,4 +1,4 @@
-import { Application, CoercibleProperty, Color, Enums, Font, Frame, ImageSource, Property, Utils, getTransformedText, isIOS } from '@nativescript/core';
+import { Application, CoercibleProperty, Color, Enums, Font, Frame, ImageSource, Property, Utils, getTransformedText, isIOS, View } from '@nativescript/core';
 import { TabStrip } from '@nativescript-community/ui-material-core/tab-navigation-base/tab-strip';
 import { TabStripItem } from '@nativescript-community/ui-material-core/tab-navigation-base/tab-strip-item';
 import { TabContentItem } from '@nativescript-community/ui-material-core/tab-navigation-base/tab-content-item';
@@ -14,13 +14,15 @@ const DEFAULT_ELEVATION = 4;
 
 const TABID = '_tabId';
 const INDEX = '_index';
+const ownerSymbol = Symbol('_owner');
 
 type PagerAdapter = new (owner: Tabs) => androidx.viewpager.widget.PagerAdapter;
 
 // eslint-disable-next-line no-redeclare
 let PagerAdapter: PagerAdapter;
 let TabsBar: any;
 let appResources: android.content.res.Resources;
+let AttachStateChangeListener: any;
 
 function makeFragmentName(viewId: number, id: number): string {
     return 'android:viewpager:' + viewId + ':' + id;
@@ -326,8 +328,33 @@ function initializeNativeClasses() {
         }
     }
 
+    @NativeClass
+    @Interfaces([android.view.View.OnAttachStateChangeListener])
+    class AttachListener extends java.lang.Object implements android.view.View.OnAttachStateChangeListener {
+        constructor() {
+            super();
+
+            return global.__native(this);
+        }
+
+        onViewAttachedToWindow(view: android.view.View): void {
+            const owner: View = view[ownerSymbol];
+            if (owner) {
+                owner._onAttachedToWindow();
+            }
+        }
+
+        onViewDetachedFromWindow(view: android.view.View): void {
+            const owner: View = view[ownerSymbol];
+            if (owner) {
+                owner._onDetachedFromWindow();
+            }
+        }
+    }
+
     PagerAdapter = FragmentPagerAdapter;
     TabsBar = TabsBarImplementation;
+    AttachStateChangeListener = new AttachListener();
     appResources = Application.android.context.getResources();
 }
 
@@ -374,6 +401,7 @@ export class Tabs extends TabsBase {
     private _selectedItemColor: Color;
     private _unSelectedItemColor: Color;
     fragments: androidx.fragment.app.Fragment[] = [];
+    private _attachedToWindow = false;
 
     constructor() {
         super();
@@ -457,13 +485,36 @@ export class Tabs extends TabsBase {
         const nativeView: any = this.nativeViewProtected;
         this._tabsBar = nativeView.tabsBar;
 
+        // nativeView.addOnAttachStateChangeListener(AttachStateChangeListener);
+        nativeView[ownerSymbol] = this;
+
         const viewPager = nativeView.viewPager;
         viewPager.setId(this._androidViewId);
         this._viewPager = viewPager;
         this._pagerAdapter = viewPager.adapter;
         (this._pagerAdapter as any).owner = this;
     }
 
+    _onAttachedToWindow(): void {
+        super._onAttachedToWindow();
+
+        // _onAttachedToWindow called from OS again after it was detach
+        // TODO: Consider testing and removing it when update to androidx.fragment:1.2.0
+        if (this._manager && this._manager.isDestroyed()) {
+            return;
+        }
+
+        this._attachedToWindow = true;
+        this._viewPager.setCurrentItem(this.selectedIndex, false);
+    }
+
+    _onDetachedFromWindow(): void {
+        super._onDetachedFromWindow();
+        this.disposeCurrentFragments();
+
+        this._attachedToWindow = false;
+    }
+
     public _loadUnloadTabItems(newIndex: number) {
         const items = this.items;
         if (!items) {
@@ -538,6 +589,9 @@ export class Tabs extends TabsBase {
         (this._pagerAdapter as any).owner = null;
         this._pagerAdapter = null;
 
+        this.nativeViewProtected.removeOnAttachStateChangeListener(AttachStateChangeListener);
+        this.nativeViewProtected[ownerSymbol] = null;
+
         this._tabsBar = null;
         this._viewPager = null;
         super.disposeNativeView();