Fix issues with recyclerview items with margins

Author: jacob-tabak

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

@@ -4,6 +4,7 @@
 import android.support.v7.widget.LinearLayoutManager;
 import android.support.v7.widget.RecyclerView;
 import android.view.View;
+import android.view.ViewGroup;
 import android.widget.LinearLayout;
 
 import com.timehop.stickyheadersrecyclerview.caching.HeaderProvider;
@@ -110,15 +111,25 @@ public void initHeaderBounds(Rect bounds, RecyclerView recyclerView, View header
   private void initDefaultHeaderOffset(Rect headerMargins, RecyclerView recyclerView, View header, View firstView, int orientation) {
     int translationX, translationY;
     mDimensionCalculator.initMargins(mTempRect1, header);
+
+    ViewGroup.LayoutParams layoutParams = firstView.getLayoutParams();
+    int leftMargin = 0;
+    int topMargin = 0;
+    if (layoutParams instanceof ViewGroup.MarginLayoutParams) {
+      ViewGroup.MarginLayoutParams marginLayoutParams = (ViewGroup.MarginLayoutParams) layoutParams;
+      leftMargin = marginLayoutParams.leftMargin;
+      topMargin = marginLayoutParams.topMargin;
+    }
+
     if (orientation == LinearLayoutManager.VERTICAL) {
-      translationX = firstView.getLeft() + mTempRect1.left;
+      translationX = firstView.getLeft() - leftMargin + mTempRect1.left;
       translationY = Math.max(
-          firstView.getTop() - header.getHeight() - mTempRect1.bottom,
+          firstView.getTop() - topMargin - header.getHeight() - mTempRect1.bottom,
           getListTop(recyclerView) + mTempRect1.top);
     } else {
-      translationY = firstView.getTop() + mTempRect1.top;
+      translationY = firstView.getTop() - topMargin + mTempRect1.top;
       translationX = Math.max(
-          firstView.getLeft() - header.getWidth() - mTempRect1.right,
+          firstView.getLeft() - leftMargin - header.getWidth() - mTempRect1.right,
           getListLeft(recyclerView) + mTempRect1.left);
     }