From 44c00be01a5e1666cfce83630f91d3301594ef0b Mon Sep 17 00:00:00 2001
From: Matt Robinson <mattro@oit.rutgers.edu>
Date: Wed, 13 Jul 2016 14:55:32 -0400
Subject: [PATCH] Swappable returns a boolean for saying if the swap occured or
 not

---
 lib-core-slh/build.gradle                              |  2 +-
 .../com/nhaarman/listviewanimations/ArrayAdapter.java  |  3 ++-
 .../listviewanimations/BaseAdapterDecorator.java       |  4 +++-
 .../nhaarman/listviewanimations/util/Swappable.java    |  2 +-
 .../itemmanipulation/dragdrop/DragAndDropHandler.java  | 10 ++++++----
 5 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/lib-core-slh/build.gradle b/lib-core-slh/build.gradle
index 3619c8f7..75ff67db 100644
--- a/lib-core-slh/build.gradle
+++ b/lib-core-slh/build.gradle
@@ -62,4 +62,4 @@ android {
         textOutput 'stdout'
         warningsAsErrors true
     }
-}
\ No newline at end of file
+}
diff --git a/lib-core/src/main/java/com/nhaarman/listviewanimations/ArrayAdapter.java b/lib-core/src/main/java/com/nhaarman/listviewanimations/ArrayAdapter.java
index 56cb9dd3..0add7788 100644
--- a/lib-core/src/main/java/com/nhaarman/listviewanimations/ArrayAdapter.java
+++ b/lib-core/src/main/java/com/nhaarman/listviewanimations/ArrayAdapter.java
@@ -137,10 +137,11 @@ public T remove(final int location) {
     }
 
     @Override
-    public void swapItems(final int positionOne, final int positionTwo) {
+    public boolean swapItems(final int positionOne, final int positionTwo) {
         T firstItem = mItems.set(positionOne, getItem(positionTwo));
         notifyDataSetChanged();
         mItems.set(positionTwo, firstItem);
+        return true;
     }
 
     public void propagateNotifyDataSetChanged(@NonNull final BaseAdapter slavedAdapter) {
diff --git a/lib-core/src/main/java/com/nhaarman/listviewanimations/BaseAdapterDecorator.java b/lib-core/src/main/java/com/nhaarman/listviewanimations/BaseAdapterDecorator.java
index 5f8ae49a..1ce1e8d3 100644
--- a/lib-core/src/main/java/com/nhaarman/listviewanimations/BaseAdapterDecorator.java
+++ b/lib-core/src/main/java/com/nhaarman/listviewanimations/BaseAdapterDecorator.java
@@ -227,12 +227,14 @@ public Object[] getSections() {
     }
 
     @Override
-    public void swapItems(final int positionOne, final int positionTwo) {
+    public boolean swapItems(final int positionOne, final int positionTwo) {
         if (mDecoratedBaseAdapter instanceof Swappable) {
             ((Swappable) mDecoratedBaseAdapter).swapItems(positionOne, positionTwo);
+            return true;
         } else {
             Log.w("ListViewAnimations", "Warning: swapItems called on an adapter that does not implement Swappable!");
         }
+        return false;
     }
 
     @Override
diff --git a/lib-core/src/main/java/com/nhaarman/listviewanimations/util/Swappable.java b/lib-core/src/main/java/com/nhaarman/listviewanimations/util/Swappable.java
index c9d639d9..2681028d 100644
--- a/lib-core/src/main/java/com/nhaarman/listviewanimations/util/Swappable.java
+++ b/lib-core/src/main/java/com/nhaarman/listviewanimations/util/Swappable.java
@@ -29,5 +29,5 @@ public interface Swappable {
      * @param positionOne First adapter position.
      * @param positionTwo Second adapter position.
      */
-    void swapItems(int positionOne, int positionTwo);
+    boolean swapItems(int positionOne, int positionTwo);
 }
\ No newline at end of file
diff --git a/lib-manipulation/src/main/java/com/nhaarman/listviewanimations/itemmanipulation/dragdrop/DragAndDropHandler.java b/lib-manipulation/src/main/java/com/nhaarman/listviewanimations/itemmanipulation/dragdrop/DragAndDropHandler.java
index 26c231ba..5381ad2d 100644
--- a/lib-manipulation/src/main/java/com/nhaarman/listviewanimations/itemmanipulation/dragdrop/DragAndDropHandler.java
+++ b/lib-manipulation/src/main/java/com/nhaarman/listviewanimations/itemmanipulation/dragdrop/DragAndDropHandler.java
@@ -430,11 +430,13 @@ private void switchViews(final View switchView, final long switchId, final float
         final int switchViewPosition = mWrapper.getPositionForView(switchView);
         int mobileViewPosition = mWrapper.getPositionForView(mMobileView);
 
-        ((Swappable) mAdapter).swapItems(switchViewPosition - mWrapper.getHeaderViewsCount(), mobileViewPosition - mWrapper.getHeaderViewsCount());
-        ((BaseAdapter) mAdapter).notifyDataSetChanged();
+        boolean didSwap = ((Swappable) mAdapter).swapItems(switchViewPosition - mWrapper.getHeaderViewsCount(), mobileViewPosition - mWrapper.getHeaderViewsCount());
+        if (didSwap) {
+            ((BaseAdapter) mAdapter).notifyDataSetChanged();
 
-        mHoverDrawable.shift(switchView.getHeight());
-        mSwitchViewAnimator.animateSwitchView(switchId, translationY);
+            mHoverDrawable.shift(switchView.getHeight());
+            mSwitchViewAnimator.animateSwitchView(switchId, translationY);
+        }
     }
 
     /**