reset state of adapter

Author: anod

src/main/java/info/anodsplace/android/widget/recyclerview/MergeRecyclerAdapter.java

@@ -130,6 +130,7 @@ protected RecyclerView.Adapter getAdapterOffsetForItem(final int position) {
 		int i = 0;
 		int count = 0;
 
+		mAdapterOffset = 0;
 		while (i < adapterCount) {
 			RecyclerView.Adapter adapter = mAdapters.get(i);
 			int newCount = count + adapter.getItemCount();