From 911e1384c35cf8cbc19d348df16415b199a94932 Mon Sep 17 00:00:00 2001
From: Janic Duplessis <janicduplessis@gmail.com>
Date: Mon, 6 Jun 2016 19:25:45 -0400
Subject: [PATCH] Fix LayoutAnimation Android bug when adding and removing
 views at the same time

---
 .../uimanager/NativeViewHierarchyManager.java | 17 +++++++-
 .../LayoutAnimationController.java            | 40 +++++++++++++++++++
 2 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/ReactAndroid/src/main/java/com/facebook/react/uimanager/NativeViewHierarchyManager.java b/ReactAndroid/src/main/java/com/facebook/react/uimanager/NativeViewHierarchyManager.java
index 36ab83c8fa871f..d7728cdc524a6a 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/uimanager/NativeViewHierarchyManager.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/uimanager/NativeViewHierarchyManager.java
@@ -352,6 +352,7 @@ public void manageChildren(
             arrayContains(tagsToDelete, viewToRemove.getId())) {
           // The view will be removed and dropped by the 'delete' layout animation
           // instead, so do nothing
+          mLayoutAnimator.addViewAnimatingDeletion(viewToRemove);
         } else {
           viewManager.removeViewAt(viewToManage, indexToRemove);
         }
@@ -375,7 +376,20 @@ public void manageChildren(
                       viewsToAdd,
                       tagsToDelete));
         }
-        viewManager.addView(viewToManage, viewToAdd, viewAtIndex.mIndex);
+
+        // When performing layout delete animations views are not removed immediately
+        // from their container so we need to offset the insert index if a view
+        // that is going to be removed is before the view we want to insert.
+        int addViewIndex = viewAtIndex.mIndex;
+        if (mLayoutAnimator.isAnimatingViewDeletion()) {
+          for(int index = 0; index < viewAtIndex.mIndex; index++) {
+            if (mLayoutAnimator.isViewAnimatingDeletion(viewManager.getChildAt(viewToManage, index))) {
+              addViewIndex++;
+            }
+          }
+        }
+
+        viewManager.addView(viewToManage, viewToAdd, addViewIndex);
       }
     }
 
@@ -399,6 +413,7 @@ public void manageChildren(
           mLayoutAnimator.deleteView(viewToDestroy, new LayoutAnimationListener() {
             @Override
             public void onAnimationEnd() {
+              mLayoutAnimator.removeViewAnimatingDeletion(viewToDestroy);
               viewManager.removeView(viewToManage, viewToDestroy);
               dropView(viewToDestroy);
             }
diff --git a/ReactAndroid/src/main/java/com/facebook/react/uimanager/layoutanimation/LayoutAnimationController.java b/ReactAndroid/src/main/java/com/facebook/react/uimanager/layoutanimation/LayoutAnimationController.java
index d5a08e6b264ac5..29dbfdc3522700 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/uimanager/layoutanimation/LayoutAnimationController.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/uimanager/layoutanimation/LayoutAnimationController.java
@@ -2,6 +2,9 @@
 
 package com.facebook.react.uimanager.layoutanimation;
 
+import java.util.ArrayList;
+import java.util.List;
+
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.NotThreadSafe;
 
@@ -29,6 +32,8 @@ public class LayoutAnimationController {
   private final AbstractLayoutAnimation mLayoutDeleteAnimation = new LayoutDeleteAnimation();
   private boolean mShouldAnimateLayout;
 
+  private List<View> mDeleteAnimatedViews = new ArrayList<>();
+
   public void initializeFromConfig(final @Nullable ReadableMap config) {
     if (!ENABLED) {
       return;
@@ -138,6 +143,41 @@ public void onAnimationEnd(Animation anim) {
     }
   }
 
+  /**
+   * Add a view to list of views that are being deleted with an animation.
+   *
+   * @param view View to add
+   */
+  public void addViewAnimatingDeletion(View view) {
+    mDeleteAnimatedViews.add(view);
+  }
+
+  /**
+   * Remove a view to list of views that are being deleted with an animation.
+   *
+   * @param view View to remove
+   */
+  public void removeViewAnimatingDeletion(View view) {
+    mDeleteAnimatedViews.remove(view);
+  }
+
+  /**
+   * Returns if the view is being deleted with an animation.
+   *
+   * @param view View to check
+   * @return If it is being animated
+   */
+  public boolean isViewAnimatingDeletion(View view) {
+    return mDeleteAnimatedViews.contains(view);
+  }
+
+  /**
+   * Returns if there are any view being deleted with an animation.
+   */
+  public boolean isAnimatingViewDeletion() {
+    return mDeleteAnimatedViews.size() > 0;
+  }
+
   /**
    * Disables user interactions for a view and all it's subviews.
    */