Made notifications granular

This allows the recycler view to animate the changes.

Author: puf

library/src/androidTest/java/com/firebase/ui/FirebaseArrayOfObjectsTest.java

@@ -154,7 +154,7 @@ private Bean getBean(FirebaseArray array, int index) {
     public static void runAndWaitUntil(final FirebaseArray array, Firebase ref, Runnable task, Callable<Boolean> done) throws InterruptedException {
         final java.util.concurrent.Semaphore semaphore = new java.util.concurrent.Semaphore(0);
         array.setOnChangedListener(new FirebaseArray.OnChangedListener() {
-            public void onChanged() {
+            public void onChanged(FirebaseArray.OnChangedListener.EventType type, int index, int oldIndex) {
                 semaphore.release();
             }
         });

library/src/androidTest/java/com/firebase/ui/FirebaseArrayTest.java

@@ -125,7 +125,7 @@ private static void print(FirebaseArray array) {
     public static void runAndWaitUntil(final FirebaseArray array, Firebase ref, Runnable task, Callable<Boolean> done) throws InterruptedException {
         final java.util.concurrent.Semaphore semaphore = new java.util.concurrent.Semaphore(0);
         array.setOnChangedListener(new FirebaseArray.OnChangedListener() {
-            public void onChanged() {
+            public void onChanged(FirebaseArray.OnChangedListener.EventType type, int index, int oldIndex) {
                 semaphore.release();
             }
         });

library/src/main/java/com/firebase/ui/FirebaseArray.java

@@ -3,13 +3,15 @@
 import com.firebase.client.*;
 
 import java.util.ArrayList;
+import java.util.Collections;
 
 /**
  * This class implements an array-like collection on top of a Firebase location.
  */
 class FirebaseArray implements ChildEventListener {
     public interface OnChangedListener {
-        void onChanged();
+        enum EventType { Added, Changed, Removed, Moved }
+        void onChanged(EventType type, int index, int oldIndex);
     }
 
     private Query mQuery;
@@ -53,25 +55,27 @@ public void onChildAdded(DataSnapshot snapshot, String previousChildKey) {
             index = getIndexForKey(previousChildKey) + 1;
         }
         mSnapshots.add(index, snapshot);
-        notifyChangedListeners();
+        notifyChangedListeners(OnChangedListener.EventType.Added, index);
     }
 
     public void onChildChanged(DataSnapshot snapshot, String previousChildKey) {
         int index = getIndexForKey(snapshot.getKey());
         mSnapshots.set(index, snapshot);
-        notifyChangedListeners();
+        notifyChangedListeners(OnChangedListener.EventType.Changed, index);
     }
 
     public void onChildRemoved(DataSnapshot snapshot) {
         int index = getIndexForKey(snapshot.getKey());
         mSnapshots.remove(index);
-        notifyChangedListeners();
+        notifyChangedListeners(OnChangedListener.EventType.Removed, index);
     }
 
     public void onChildMoved(DataSnapshot snapshot, String previousChildKey) {
-        onChildRemoved(snapshot);
-        onChildAdded(snapshot, previousChildKey);
-        // TODO: this will send two change notifications, which is wrong
+        int oldIndex = getIndexForKey(snapshot.getKey());
+        mSnapshots.remove(oldIndex);
+        int newIndex = previousChildKey == null ? 0 : (getIndexForKey(previousChildKey) + 1);
+        mSnapshots.add(newIndex, snapshot);
+        notifyChangedListeners(OnChangedListener.EventType.Moved, newIndex, oldIndex);
     }
 
     public void onCancelled(FirebaseError firebaseError) {
@@ -82,9 +86,12 @@ public void onCancelled(FirebaseError firebaseError) {
     public void setOnChangedListener(OnChangedListener listener) {
         mListener = listener;
     }
-    protected void notifyChangedListeners() {
+    protected void notifyChangedListeners(OnChangedListener.EventType type, int index) {
+        notifyChangedListeners(type, index, -1);
+    }
+    protected void notifyChangedListeners(OnChangedListener.EventType type, int index, int oldIndex) {
         if (mListener != null) {
-            mListener.onChanged();
+            mListener.onChanged(type, index, oldIndex);
         }
     }
 }

library/src/main/java/com/firebase/ui/FirebaseListAdapter.java

@@ -40,7 +40,7 @@ public FirebaseListAdapter(Class<T> modelClass, int layout, Activity activity, Q
         mSnapshots = new FirebaseArray(ref);
         mSnapshots.setOnChangedListener(new FirebaseArray.OnChangedListener() {
             @Override
-            public void onChanged() {
+            public void onChanged(EventType type, int index, int oldIndex) {
                 notifyDataSetChanged();
             }
         });

library/src/main/java/com/firebase/ui/FirebaseRecyclerViewAdapter.java

@@ -39,8 +39,23 @@ public FirebaseRecyclerViewAdapter(Query ref, Class<T> modelClass) {
         // TODO: implement separate notifications for added, removed, changed and moved
         mSnapshots.setOnChangedListener(new FirebaseArray.OnChangedListener() {
             @Override
-            public void onChanged() {
-                notifyDataSetChanged();
+            public void onChanged(EventType type, int index, int oldIndex) {
+                switch (type) {
+                    case Added:
+                        notifyItemInserted(index);
+                        break;
+                    case Changed:
+                        notifyItemChanged(index);
+                        break;
+                    case Removed:
+                        notifyItemRemoved(index);
+                        break;
+                    case Moved:
+                        notifyItemMoved(oldIndex, index);
+                        break;
+                    default:
+                        throw new IllegalStateException("Incomplete case statement");
+                }
             }
         });