From 6aac3201034642f4331f18566e291247c3bd8efd Mon Sep 17 00:00:00 2001
From: Manol Donev <manol.donev@gmail.com>
Date: Thu, 6 Dec 2018 16:35:10 +0200
Subject: [PATCH 1/4] fix(android): nested fragment disappears on parent
 fragment removal

---
 tns-core-modules/ui/frame/fragment.android.ts | 41 +++++++++++++++++--
 .../ui/frame/fragment.transitions.android.ts  | 15 ++++++-
 .../ui/tab-view/tab-view.android.ts           | 41 +++++++++++++++++--
 3 files changed, 90 insertions(+), 7 deletions(-)

diff --git a/tns-core-modules/ui/frame/fragment.android.ts b/tns-core-modules/ui/frame/fragment.android.ts
index 86b3ccc2cf..df06e6ccd3 100644
--- a/tns-core-modules/ui/frame/fragment.android.ts
+++ b/tns-core-modules/ui/frame/fragment.android.ts
@@ -1,10 +1,22 @@
 import { AndroidFragmentCallbacks, setFragmentCallbacks, setFragmentClass } from "./frame";
+import { AnimationType } from "./fragment.transitions";
+
+function createDummyAnimator(duration: number): android.animation.Animator {
+    const alphaValues = Array.create("float", 2);
+    alphaValues[0] = 1;
+    alphaValues[1] = 1;
+    
+    const animator = android.animation.ObjectAnimator.ofFloat(null, "alpha", alphaValues);
+    animator.setDuration(duration);
+
+    return animator;
+}
 
 @JavaProxy("com.tns.FragmentClass")
 class FragmentClass extends android.support.v4.app.Fragment {
     // This field is updated in the frame module upon `new` (although hacky this eases the Fragment->callbacks association a lot)
     private _callbacks: AndroidFragmentCallbacks;
-
+    
     constructor() {
         super();
         return global.__native(this);
@@ -15,8 +27,22 @@ class FragmentClass extends android.support.v4.app.Fragment {
     }
 
     public onCreateAnimator(transit: number, enter: boolean, nextAnim: number): android.animation.Animator {
-        let result = this._callbacks.onCreateAnimator(this, transit, enter, nextAnim, super.onCreateAnimator);
-        return result;
+        // [nested frames / fragments] apply dummy animator to the nested fragment with
+        // the same duration as the exit animator of the removing parent fragment to work around
+        // https://code.google.com/p/android/issues/detail?id=55228 (child fragments disappear
+        // when parent fragment is removed as all children are first removed from parent)
+        if (!enter) {
+            const removingParentFragment = this.getRemovingParentFragment();
+            if (removingParentFragment) {
+                const parentAnimator = removingParentFragment.onCreateAnimator(transit, enter, AnimationType.exitFakeResourceId);
+                if (parentAnimator) {
+                    const duration = parentAnimator.getDuration();
+                    return createDummyAnimator(duration);
+                }
+            }
+        }
+
+        return this._callbacks.onCreateAnimator(this, transit, enter, nextAnim, super.onCreateAnimator);
     }
 
     public onStop(): void {
@@ -57,6 +83,15 @@ class FragmentClass extends android.support.v4.app.Fragment {
             super.toString();
         }
     }
+
+    private getRemovingParentFragment(): android.support.v4.app.Fragment {
+        let parentFragment = this.getParentFragment();
+        while (parentFragment && !parentFragment.isRemoving()) {
+            parentFragment = parentFragment.getParentFragment();
+        }
+    
+        return parentFragment;
+    }
 }
 
 setFragmentClass(FragmentClass);
\ No newline at end of file
diff --git a/tns-core-modules/ui/frame/fragment.transitions.android.ts b/tns-core-modules/ui/frame/fragment.transitions.android.ts
index 43eefeeff3..95d682b03e 100644
--- a/tns-core-modules/ui/frame/fragment.transitions.android.ts
+++ b/tns-core-modules/ui/frame/fragment.transitions.android.ts
@@ -86,7 +86,20 @@ export function _setAndroidFragmentTransitions(
         name = navigationTransition.name ? navigationTransition.name.toLowerCase() : "";
     }
 
-    let useLollipopTransition = name && (name.indexOf("slide") === 0 || name === "fade" || name === "explode") && sdkVersion() >= 21;
+    let useLollipopTransition = !!(name && (name.indexOf("slide") === 0 || name === "fade" || name === "explode") && sdkVersion() >= 21);
+    // [nested frames / fragments] force disable lollipop transitions in case nested fragments 
+    // are detected as applying dummy animator to the nested fragment with the same duration as 
+    // the exit animator of the removing parent fragment as a workaround for 
+    // https://code.google.com/p/android/issues/detail?id=55228 works only if custom animations are
+    // used
+    // NOTE: this effectively means you cannot use Explode transition in nested frames scenarios as
+    // we have implementations only for slide, fade, and flip
+    if (currentFragment && 
+        currentFragment.getChildFragmentManager() &&
+        currentFragment.getChildFragmentManager().getFragments().toArray().length > 0) {
+        useLollipopTransition = false;
+    }
+    
     if (!animated) {
         name = "none";
     } else if (transition) {
diff --git a/tns-core-modules/ui/tab-view/tab-view.android.ts b/tns-core-modules/ui/tab-view/tab-view.android.ts
index 8b89422d6c..b83562e361 100644
--- a/tns-core-modules/ui/tab-view/tab-view.android.ts
+++ b/tns-core-modules/ui/tab-view/tab-view.android.ts
@@ -12,6 +12,7 @@ import { textTransformProperty, TextTransform, getTransformedText } from "../tex
 import { fromFileOrResource } from "../../image-source";
 import { RESOURCE_PREFIX, ad } from "../../utils/utils";
 import { Frame } from "../frame";
+import { AnimationType } from "../frame/fragment.transitions";
 
 export * from "./tab-view-common";
 
@@ -40,6 +41,17 @@ function getTabById(id: number): TabView {
     return ref && ref.get();
 }
 
+function createDummyAnimator(duration: number): android.animation.Animator {
+    const alphaValues = Array.create("float", 2);
+    alphaValues[0] = 1;
+    alphaValues[1] = 1;
+    
+    const animator = android.animation.ObjectAnimator.ofFloat(null, "alpha", alphaValues);
+    animator.setDuration(duration);
+
+    return animator;
+}
+
 function initializeNativeClasses() {
     if (PagerAdapter) {
         return;
@@ -55,7 +67,6 @@ function initializeNativeClasses() {
         }
 
         static newInstance(tabId: number, index: number): TabFragmentImplementation {
-
             const args = new android.os.Bundle();
             args.putInt(TABID, tabId);
             args.putInt(INDEX, index);
@@ -74,14 +85,38 @@ function initializeNativeClasses() {
             }
         }
 
+        public onCreateAnimator(transit: number, enter: boolean, nextAnim: number): android.animation.Animator {
+            // [nested frames / fragments] apply dummy animator to the nested fragment with
+            // the same duration as the exit animator of the removing parent fragment to work around
+            // https://code.google.com/p/android/issues/detail?id=55228 (child fragments disappear
+            // when parent fragment is removed as all children are first removed from parent)
+            if (!enter) {
+                const removingParentFragment = this.getRemovingParentFragment();
+                if (removingParentFragment) {
+                    const parentAnimator = removingParentFragment.onCreateAnimator(transit, enter, AnimationType.exitFakeResourceId);
+                    if (parentAnimator) {
+                        const duration = parentAnimator.getDuration();
+                        return createDummyAnimator(duration);
+                    }
+                }
+            }
+
+            return super.onCreateAnimator(transit, enter, nextAnim);
+        }
+
         public onCreateView(inflater: android.view.LayoutInflater, container: android.view.ViewGroup, savedInstanceState: android.os.Bundle): android.view.View {
             const tabItem = this.tab.items[this.index];
 
             return tabItem.view.nativeViewProtected;
         }
 
-        public onDestroyView() {
-            super.onDestroyView();
+        private getRemovingParentFragment(): android.support.v4.app.Fragment {
+            let parentFragment = this.getParentFragment();
+            while (parentFragment && !parentFragment.isRemoving()) {
+                parentFragment = parentFragment.getParentFragment();
+            }
+        
+            return parentFragment;
         }
     }
 

From 8a677e74fb1d492269896aad057581c966744f0c Mon Sep 17 00:00:00 2001
From: Manol Donev <manol.donev@gmail.com>
Date: Thu, 6 Dec 2018 17:21:30 +0200
Subject: [PATCH 2/4] fix flip transition with nested frames hack

---
 tns-core-modules/ui/frame/fragment.android.ts             | 5 ++++-
 tns-core-modules/ui/tab-view/tab-view.android.ts          | 5 ++++-
 tns-core-modules/ui/transition/flip-transition.android.ts | 1 +
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/tns-core-modules/ui/frame/fragment.android.ts b/tns-core-modules/ui/frame/fragment.android.ts
index df06e6ccd3..e2b133b306 100644
--- a/tns-core-modules/ui/frame/fragment.android.ts
+++ b/tns-core-modules/ui/frame/fragment.android.ts
@@ -37,7 +37,10 @@ class FragmentClass extends android.support.v4.app.Fragment {
                 const parentAnimator = removingParentFragment.onCreateAnimator(transit, enter, AnimationType.exitFakeResourceId);
                 if (parentAnimator) {
                     const duration = parentAnimator.getDuration();
-                    return createDummyAnimator(duration);
+
+                    // duration will be -1 if an animator is an AnimatorSet (like our FlipTransition)
+                    // and it does not have its duration set
+                    return createDummyAnimator(duration > 0 ? duration : 0);
                 }
             }
         }
diff --git a/tns-core-modules/ui/tab-view/tab-view.android.ts b/tns-core-modules/ui/tab-view/tab-view.android.ts
index b83562e361..0b94990c03 100644
--- a/tns-core-modules/ui/tab-view/tab-view.android.ts
+++ b/tns-core-modules/ui/tab-view/tab-view.android.ts
@@ -96,7 +96,10 @@ function initializeNativeClasses() {
                     const parentAnimator = removingParentFragment.onCreateAnimator(transit, enter, AnimationType.exitFakeResourceId);
                     if (parentAnimator) {
                         const duration = parentAnimator.getDuration();
-                        return createDummyAnimator(duration);
+                        
+                        // duration will be -1 if an animator is an AnimatorSet (like our FlipTransition)
+                        // and it does not have its duration set
+                        return createDummyAnimator(duration > 0 ? duration : 0);
                     }
                 }
             }
diff --git a/tns-core-modules/ui/transition/flip-transition.android.ts b/tns-core-modules/ui/transition/flip-transition.android.ts
index 612ab01177..88e61d3dff 100644
--- a/tns-core-modules/ui/transition/flip-transition.android.ts
+++ b/tns-core-modules/ui/transition/flip-transition.android.ts
@@ -112,6 +112,7 @@ export class FlipTransition extends Transition {
         }
 
         animatorSet.playTogether(objectAnimators);
+        animatorSet.setDuration(fullDuration);
         return animatorSet;
     }
 }

From cb910c6275b486c891779cc7eef2872e368e58d8 Mon Sep 17 00:00:00 2001
From: Manol Donev <manol.donev@gmail.com>
Date: Mon, 10 Dec 2018 19:29:38 +0200
Subject: [PATCH 3/4] refactor(android): extract FragmentBase class

---
 tns-core-modules/ui/frame/fragment.android.ts | 41 +----------------
 tns-core-modules/ui/frame/frame.android.ts    |  8 +++-
 .../ui/tab-view/tab-view.android.ts           | 45 +------------------
 .../ui/transition/flip-transition.android.ts  |  1 -
 .../android/org.nativescript.widgets.d.ts     |  6 +++
 5 files changed, 15 insertions(+), 86 deletions(-)

diff --git a/tns-core-modules/ui/frame/fragment.android.ts b/tns-core-modules/ui/frame/fragment.android.ts
index e2b133b306..99da04835e 100644
--- a/tns-core-modules/ui/frame/fragment.android.ts
+++ b/tns-core-modules/ui/frame/fragment.android.ts
@@ -1,19 +1,7 @@
 import { AndroidFragmentCallbacks, setFragmentCallbacks, setFragmentClass } from "./frame";
-import { AnimationType } from "./fragment.transitions";
-
-function createDummyAnimator(duration: number): android.animation.Animator {
-    const alphaValues = Array.create("float", 2);
-    alphaValues[0] = 1;
-    alphaValues[1] = 1;
-    
-    const animator = android.animation.ObjectAnimator.ofFloat(null, "alpha", alphaValues);
-    animator.setDuration(duration);
-
-    return animator;
-}
 
 @JavaProxy("com.tns.FragmentClass")
-class FragmentClass extends android.support.v4.app.Fragment {
+class FragmentClass extends org.nativescript.widgets.FragmentBase {
     // This field is updated in the frame module upon `new` (although hacky this eases the Fragment->callbacks association a lot)
     private _callbacks: AndroidFragmentCallbacks;
     
@@ -27,24 +15,6 @@ class FragmentClass extends android.support.v4.app.Fragment {
     }
 
     public onCreateAnimator(transit: number, enter: boolean, nextAnim: number): android.animation.Animator {
-        // [nested frames / fragments] apply dummy animator to the nested fragment with
-        // the same duration as the exit animator of the removing parent fragment to work around
-        // https://code.google.com/p/android/issues/detail?id=55228 (child fragments disappear
-        // when parent fragment is removed as all children are first removed from parent)
-        if (!enter) {
-            const removingParentFragment = this.getRemovingParentFragment();
-            if (removingParentFragment) {
-                const parentAnimator = removingParentFragment.onCreateAnimator(transit, enter, AnimationType.exitFakeResourceId);
-                if (parentAnimator) {
-                    const duration = parentAnimator.getDuration();
-
-                    // duration will be -1 if an animator is an AnimatorSet (like our FlipTransition)
-                    // and it does not have its duration set
-                    return createDummyAnimator(duration > 0 ? duration : 0);
-                }
-            }
-        }
-
         return this._callbacks.onCreateAnimator(this, transit, enter, nextAnim, super.onCreateAnimator);
     }
 
@@ -86,15 +56,6 @@ class FragmentClass extends android.support.v4.app.Fragment {
             super.toString();
         }
     }
-
-    private getRemovingParentFragment(): android.support.v4.app.Fragment {
-        let parentFragment = this.getParentFragment();
-        while (parentFragment && !parentFragment.isRemoving()) {
-            parentFragment = parentFragment.getParentFragment();
-        }
-    
-        return parentFragment;
-    }
 }
 
 setFragmentClass(FragmentClass);
\ No newline at end of file
diff --git a/tns-core-modules/ui/frame/frame.android.ts b/tns-core-modules/ui/frame/frame.android.ts
index 417d817bb2..edfdbef65e 100644
--- a/tns-core-modules/ui/frame/frame.android.ts
+++ b/tns-core-modules/ui/frame/frame.android.ts
@@ -742,7 +742,13 @@ class FragmentCallbacksImplementation implements AndroidFragmentCallbacks {
     }
 
     @profile
-    public onCreateAnimator(fragment: android.support.v4.app.Fragment, transit: number, enter: boolean, nextAnim: number, superFunc: Function): android.animation.Animator {
+    public onCreateAnimator(fragment: org.nativescript.widgets.FragmentBase, transit: number, enter: boolean, nextAnim: number, superFunc: Function): android.animation.Animator {
+        // HACK: FragmentBase class MUST handle removing nested fragment scenario to workaround
+        // https://code.google.com/p/android/issues/detail?id=55228
+        if (!enter && fragment.getRemovingParentFragment()) {
+            return superFunc.call(fragment, transit, enter, nextAnim);
+        }
+
         let nextAnimString: string;
         switch (nextAnim) {
             case AnimationType.enterFakeResourceId: nextAnimString = "enter"; break;
diff --git a/tns-core-modules/ui/tab-view/tab-view.android.ts b/tns-core-modules/ui/tab-view/tab-view.android.ts
index 0b94990c03..558424242a 100644
--- a/tns-core-modules/ui/tab-view/tab-view.android.ts
+++ b/tns-core-modules/ui/tab-view/tab-view.android.ts
@@ -12,7 +12,6 @@ import { textTransformProperty, TextTransform, getTransformedText } from "../tex
 import { fromFileOrResource } from "../../image-source";
 import { RESOURCE_PREFIX, ad } from "../../utils/utils";
 import { Frame } from "../frame";
-import { AnimationType } from "../frame/fragment.transitions";
 
 export * from "./tab-view-common";
 
@@ -41,23 +40,12 @@ function getTabById(id: number): TabView {
     return ref && ref.get();
 }
 
-function createDummyAnimator(duration: number): android.animation.Animator {
-    const alphaValues = Array.create("float", 2);
-    alphaValues[0] = 1;
-    alphaValues[1] = 1;
-    
-    const animator = android.animation.ObjectAnimator.ofFloat(null, "alpha", alphaValues);
-    animator.setDuration(duration);
-
-    return animator;
-}
-
 function initializeNativeClasses() {
     if (PagerAdapter) {
         return;
     }
 
-    class TabFragmentImplementation extends android.support.v4.app.Fragment {
+    class TabFragmentImplementation extends org.nativescript.widgets.FragmentBase {
         private tab: TabView;
         private index: number;
 
@@ -85,42 +73,11 @@ function initializeNativeClasses() {
             }
         }
 
-        public onCreateAnimator(transit: number, enter: boolean, nextAnim: number): android.animation.Animator {
-            // [nested frames / fragments] apply dummy animator to the nested fragment with
-            // the same duration as the exit animator of the removing parent fragment to work around
-            // https://code.google.com/p/android/issues/detail?id=55228 (child fragments disappear
-            // when parent fragment is removed as all children are first removed from parent)
-            if (!enter) {
-                const removingParentFragment = this.getRemovingParentFragment();
-                if (removingParentFragment) {
-                    const parentAnimator = removingParentFragment.onCreateAnimator(transit, enter, AnimationType.exitFakeResourceId);
-                    if (parentAnimator) {
-                        const duration = parentAnimator.getDuration();
-                        
-                        // duration will be -1 if an animator is an AnimatorSet (like our FlipTransition)
-                        // and it does not have its duration set
-                        return createDummyAnimator(duration > 0 ? duration : 0);
-                    }
-                }
-            }
-
-            return super.onCreateAnimator(transit, enter, nextAnim);
-        }
-
         public onCreateView(inflater: android.view.LayoutInflater, container: android.view.ViewGroup, savedInstanceState: android.os.Bundle): android.view.View {
             const tabItem = this.tab.items[this.index];
 
             return tabItem.view.nativeViewProtected;
         }
-
-        private getRemovingParentFragment(): android.support.v4.app.Fragment {
-            let parentFragment = this.getParentFragment();
-            while (parentFragment && !parentFragment.isRemoving()) {
-                parentFragment = parentFragment.getParentFragment();
-            }
-        
-            return parentFragment;
-        }
     }
 
     const POSITION_UNCHANGED = -1;
diff --git a/tns-core-modules/ui/transition/flip-transition.android.ts b/tns-core-modules/ui/transition/flip-transition.android.ts
index 88e61d3dff..612ab01177 100644
--- a/tns-core-modules/ui/transition/flip-transition.android.ts
+++ b/tns-core-modules/ui/transition/flip-transition.android.ts
@@ -112,7 +112,6 @@ export class FlipTransition extends Transition {
         }
 
         animatorSet.playTogether(objectAnimators);
-        animatorSet.setDuration(fullDuration);
         return animatorSet;
     }
 }
diff --git a/tns-platform-declarations/android/org.nativescript.widgets.d.ts b/tns-platform-declarations/android/org.nativescript.widgets.d.ts
index d2e4462780..ae96b44f33 100644
--- a/tns-platform-declarations/android/org.nativescript.widgets.d.ts
+++ b/tns-platform-declarations/android/org.nativescript.widgets.d.ts
@@ -164,6 +164,12 @@
                 public verticalAlignment: VerticalAlignment;
             }
 
+            export class FragmentBase extends android.support.v4.app.Fragment {
+                constructor();
+
+                public getRemovingParentFragment(): android.support.v4.app.Fragment;
+            }
+
             export enum Stretch {
                 none,
                 aspectFill,

From c4096f91faf6e6c1b269a8b8f62e20437596a95f Mon Sep 17 00:00:00 2001
From: Manol Donev <manol.donev@gmail.com>
Date: Tue, 11 Dec 2018 19:20:05 +0200
Subject: [PATCH 4/4] fix rootview reset for android nested fragments

---
 tns-core-modules/ui/frame/frame-common.ts        |  2 +-
 tns-core-modules/ui/frame/frame.android.ts       | 11 +++++------
 tns-core-modules/ui/tab-view/tab-view.android.ts |  7 ++++++-
 3 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/tns-core-modules/ui/frame/frame-common.ts b/tns-core-modules/ui/frame/frame-common.ts
index 5533f98d1d..a92093ee87 100644
--- a/tns-core-modules/ui/frame/frame-common.ts
+++ b/tns-core-modules/ui/frame/frame-common.ts
@@ -457,8 +457,8 @@ export class FrameBase extends CustomLayoutView implements FrameDefinition {
     }
 
     public _onRootViewReset(): void {
-        this._removeFromFrameStack();
         super._onRootViewReset();
+        this._removeFromFrameStack();
     }
 
     get _childrenCount(): number {
diff --git a/tns-core-modules/ui/frame/frame.android.ts b/tns-core-modules/ui/frame/frame.android.ts
index edfdbef65e..1f56a8eb2c 100644
--- a/tns-core-modules/ui/frame/frame.android.ts
+++ b/tns-core-modules/ui/frame/frame.android.ts
@@ -209,8 +209,12 @@ export class Frame extends FrameBase {
     }
 
     public _onRootViewReset(): void {
-        this.disposeCurrentFragment();
         super._onRootViewReset();
+
+        // call this AFTER the super call to ensure descendants apply their rootview-reset logic first
+        // i.e. in a scenario with nested frames / frame with tabview let the descendandt cleanup the inner
+        // fragments first, and then cleanup the parent fragments
+        this.disposeCurrentFragment();
     }
 
     onUnloaded() {
@@ -223,11 +227,6 @@ export class Frame extends FrameBase {
     }
 
     private disposeCurrentFragment(): void {
-        // 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()) {
diff --git a/tns-core-modules/ui/tab-view/tab-view.android.ts b/tns-core-modules/ui/tab-view/tab-view.android.ts
index 558424242a..6c2302e63a 100644
--- a/tns-core-modules/ui/tab-view/tab-view.android.ts
+++ b/tns-core-modules/ui/tab-view/tab-view.android.ts
@@ -555,8 +555,13 @@ export class TabView extends TabViewBase {
     }
 
     public _onRootViewReset(): void {
-        this.disposeCurrentFragments();
         super._onRootViewReset();
+        
+        // call this AFTER the super call to ensure descendants apply their rootview-reset logic first
+        // i.e. in a scenario with tab frames let the frames cleanup their fragments first, and then
+        // cleanup the tab fragments to avoid
+        // android.content.res.Resources$NotFoundException: Unable to find resource ID #0xfffffff6
+        this.disposeCurrentFragments();
     }
 
     private disposeCurrentFragments(): void {