From f8f5cb1fcf893397ccb8172921e8dfaad8ff6150 Mon Sep 17 00:00:00 2001
From: Brent Vatne <brentvatne@gmail.com>
Date: Wed, 13 Jan 2016 07:30:20 -0800
Subject: [PATCH] Fix content offset calculations when scrolling up

Summary:
The offset is cached so it doesn't need to calculate the entire height on each scroll, but the cached value was being thrown away when you scroll up -- this fixes that. Found this because it was breaking an infinite scroll view that depended on the contentOffset.y value reported from onScroll.
Closes https://github.com/facebook/react-native/pull/5278

Reviewed By: svcscm

Differential Revision: D2827556

Pulled By: dmmiller

fb-gh-sync-id: 0897b89de427cada7389113991444f57c970f980
---
 .../recyclerview/RecyclerViewBackedScrollView.java  | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/ReactAndroid/src/main/java/com/facebook/react/views/recyclerview/RecyclerViewBackedScrollView.java b/ReactAndroid/src/main/java/com/facebook/react/views/recyclerview/RecyclerViewBackedScrollView.java
index 6ebfb211c..919764f84 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/views/recyclerview/RecyclerViewBackedScrollView.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/views/recyclerview/RecyclerViewBackedScrollView.java
@@ -117,16 +117,17 @@ public class RecyclerViewBackedScrollView extends RecyclerView {
       if (mLastRequestedPosition != index) {
         int sum = 0;
         int startIndex = 0;
+
+        if (mLastRequestedPosition != -1) {
+          sum = mOffsetForLastPosition;
+          startIndex = mLastRequestedPosition;
+        }
+
         if (mLastRequestedPosition < index) {
-          if (mLastRequestedPosition != -1) {
-            sum = mOffsetForLastPosition;
-            startIndex = mLastRequestedPosition;
-          }
           for (int i = startIndex; i < index; i++) {
             sum += mReactListAdapter.mViews.get(i).getMeasuredHeight();
           }
-        }
-        else {
+        } else {
           if (index < (mLastRequestedPosition - index)) {
             for (int i = 0; i < index; i++) {
               sum += mReactListAdapter.mViews.get(i).getMeasuredHeight();