Refactored things so isPositionVisible is in its own interface, so this change will be backwards compatible.

Author: John Gray

library/src/main/java/com/timehop/stickyheadersrecyclerview/StickyRecyclerHeadersAdapter.java

@@ -36,6 +36,4 @@ public interface StickyRecyclerHeadersAdapter<VH extends RecyclerView.ViewHolder
    * @return the number of views in the adapter
    */
   int getItemCount();
-
-  boolean isPositionVisible(final int position);
 }

library/src/main/java/com/timehop/stickyheadersrecyclerview/StickyRecyclerHeadersDecoration.java

@@ -17,6 +17,7 @@
 public class StickyRecyclerHeadersDecoration extends RecyclerView.ItemDecoration {
 
   private final StickyRecyclerHeadersAdapter mAdapter;
+  private final StickyRecyclerHeadersVisibleAdapter mVisibilityAdapter;
   private final SparseArray<Rect> mHeaderRects = new SparseArray<>();
   private final HeaderProvider mHeaderProvider;
   private final OrientationProvider mOrientationProvider;
@@ -32,31 +33,36 @@ public class StickyRecyclerHeadersDecoration extends RecyclerView.ItemDecoration
 
   // TODO: Consider passing in orientation to simplify orientation accounting within calculation
   public StickyRecyclerHeadersDecoration(StickyRecyclerHeadersAdapter adapter) {
-    this(adapter, new LinearLayoutOrientationProvider(), new DimensionCalculator());
+    this(adapter, new LinearLayoutOrientationProvider(), new DimensionCalculator(), null);
+  }
+
+  public StickyRecyclerHeadersDecoration(StickyRecyclerHeadersAdapter adapter, StickyRecyclerHeadersVisibleAdapter visibilityAdapter) {
+    this(adapter, new LinearLayoutOrientationProvider(), new DimensionCalculator(), visibilityAdapter);
   }
 
   private StickyRecyclerHeadersDecoration(StickyRecyclerHeadersAdapter adapter, OrientationProvider orientationProvider,
-      DimensionCalculator dimensionCalculator) {
+      DimensionCalculator dimensionCalculator, StickyRecyclerHeadersVisibleAdapter visibilityAdapter) {
     this(adapter, orientationProvider, dimensionCalculator, new HeaderRenderer(orientationProvider),
-        new HeaderViewCache(adapter, orientationProvider));
+        new HeaderViewCache(adapter, orientationProvider), visibilityAdapter);
   }
 
   private StickyRecyclerHeadersDecoration(StickyRecyclerHeadersAdapter adapter, OrientationProvider orientationProvider,
-      DimensionCalculator dimensionCalculator, HeaderRenderer headerRenderer, HeaderProvider headerProvider) {
+      DimensionCalculator dimensionCalculator, HeaderRenderer headerRenderer, HeaderProvider headerProvider, StickyRecyclerHeadersVisibleAdapter visibilityAdapter) {
     this(adapter, headerRenderer, orientationProvider, dimensionCalculator, headerProvider,
         new HeaderPositionCalculator(adapter, headerProvider, orientationProvider,
-            dimensionCalculator));
+            dimensionCalculator), visibilityAdapter);
   }
 
   private StickyRecyclerHeadersDecoration(StickyRecyclerHeadersAdapter adapter, HeaderRenderer headerRenderer,
       OrientationProvider orientationProvider, DimensionCalculator dimensionCalculator, HeaderProvider headerProvider,
-      HeaderPositionCalculator headerPositionCalculator) {
+      HeaderPositionCalculator headerPositionCalculator, StickyRecyclerHeadersVisibleAdapter visibilityAdapter) {
     mAdapter = adapter;
     mHeaderProvider = headerProvider;
     mOrientationProvider = orientationProvider;
     mRenderer = headerRenderer;
     mDimensionCalculator = dimensionCalculator;
     mHeaderPositionCalculator = headerPositionCalculator;
+    mVisibilityAdapter = visibilityAdapter;
   }
 
   @Override
@@ -131,7 +137,7 @@ public int findHeaderPositionUnder(int x, int y) {
       Rect rect = mHeaderRects.get(mHeaderRects.keyAt(i));
       if (rect.contains(x, y)) {
         int position = mHeaderRects.keyAt(i);
-        if (mAdapter.isPositionVisible(position)) {
+        if (mVisibilityAdapter == null || mVisibilityAdapter.isPositionVisible(position)) {
           return position;
         }
       }

library/src/main/java/com/timehop/stickyheadersrecyclerview/StickyRecyclerHeadersVisibleAdapter.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2015 Lineage Labs, Inc.  All Rights Reserved.
+ *
+ * This Software contains confidential information and trade secrets of
+ * Lineage Labs, Inc.  Use, disclosure or reproduction is prohibited
+ * without the prior express written permission of Lineage Labs, Inc.
+ *
+ * LINEAGE LABS, INC MAKES NO REPRESENTATION OR WARRANTIES ABOUT THE
+ * SUITABILITY OF THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT
+ * LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+ * PARTICULAR PURPOSE, OR NON-INFRINGEMENT.  LINEAGE LABS, INC SHALL NOT
+ * BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSE AS A RESULT OF USING,
+ * MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
+ *
+ * The Licensed Software and Documentation are deemed to be commercial
+ * computer software and commercial computer software documentation as
+ * defined in FAR Sections 12.212 and DFARS Section 227.7202.
+ *
+ */
+
+package com.timehop.stickyheadersrecyclerview;
+
+/**
+ * Created by gray on 2/12/16.
+ */
+public interface StickyRecyclerHeadersVisibleAdapter {
+
+    /**
+     *
+     * Return true the specified adapter position is visible, false otherwise
+     *
+     * @param position the adapter position
+     */
+    boolean isPositionVisible(final int position);
+}