From 83ed4fe1d5ff00c2e1bd334c61f0acd3105a09ab Mon Sep 17 00:00:00 2001
From: Fabrice Di Meglio <fdimeglio@google.com>
Date: Tue, 28 Jan 2014 15:11:49 -0800
Subject: Fix bug #12066726 java.lang.NullPointerException at
 android.widget.CalendarView.onScroll(CalendarView.java:1216)

- fix the NPE by checking the validity of the child reference retrieved by View.getChildAt(...)

Change-Id: I6821448a5831c83c0931eb7bb0ef4c3f1a47247f
---
 core/java/android/widget/CalendarView.java | 52 ++++++++++++++++--------------
 1 file changed, 27 insertions(+), 25 deletions(-)

(limited to 'core/java/android/widget/CalendarView.java')

diff --git a/core/java/android/widget/CalendarView.java b/core/java/android/widget/CalendarView.java
index a87c7d29e405..d5772346aa3a 100644
--- a/core/java/android/widget/CalendarView.java
+++ b/core/java/android/widget/CalendarView.java
@@ -1488,34 +1488,36 @@ public class CalendarView extends FrameLayout {
                 child = (WeekView) view.getChildAt(offset);
             }
 
-            // Find out which month we're moving into
-            int month;
-            if (mIsScrollingUp) {
-                month = child.getMonthOfFirstWeekDay();
-            } else {
-                month = child.getMonthOfLastWeekDay();
-            }
-
-            // And how it relates to our current highlighted month
-            int monthDiff;
-            if (mCurrentMonthDisplayed == 11 && month == 0) {
-                monthDiff = 1;
-            } else if (mCurrentMonthDisplayed == 0 && month == 11) {
-                monthDiff = -1;
-            } else {
-                monthDiff = month - mCurrentMonthDisplayed;
-            }
-
-            // Only switch months if we're scrolling away from the currently
-            // selected month
-            if ((!mIsScrollingUp && monthDiff > 0) || (mIsScrollingUp && monthDiff < 0)) {
-                Calendar firstDay = child.getFirstDay();
+            if (child != null) {
+                // Find out which month we're moving into
+                int month;
                 if (mIsScrollingUp) {
-                    firstDay.add(Calendar.DAY_OF_MONTH, -DAYS_PER_WEEK);
+                    month = child.getMonthOfFirstWeekDay();
                 } else {
-                    firstDay.add(Calendar.DAY_OF_MONTH, DAYS_PER_WEEK);
+                    month = child.getMonthOfLastWeekDay();
+                }
+
+                // And how it relates to our current highlighted month
+                int monthDiff;
+                if (mCurrentMonthDisplayed == 11 && month == 0) {
+                    monthDiff = 1;
+                } else if (mCurrentMonthDisplayed == 0 && month == 11) {
+                    monthDiff = -1;
+                } else {
+                    monthDiff = month - mCurrentMonthDisplayed;
+                }
+
+                // Only switch months if we're scrolling away from the currently
+                // selected month
+                if ((!mIsScrollingUp && monthDiff > 0) || (mIsScrollingUp && monthDiff < 0)) {
+                    Calendar firstDay = child.getFirstDay();
+                    if (mIsScrollingUp) {
+                        firstDay.add(Calendar.DAY_OF_MONTH, -DAYS_PER_WEEK);
+                    } else {
+                        firstDay.add(Calendar.DAY_OF_MONTH, DAYS_PER_WEEK);
+                    }
+                    setMonthDisplayed(firstDay);
                 }
-                setMonthDisplayed(firstDay);
             }
             mPreviousScrollPosition = currScroll;
             mPreviousScrollState = mCurrentScrollState;
-- 
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