From 7da609173cb42dc5813fde09de2e1fe1218b2136 Mon Sep 17 00:00:00 2001
From: Kizito Nwose <kizitonwose@gmail.com>
Date: Tue, 30 Jul 2019 13:25:15 +0100
Subject: [PATCH] Accommodate nullable view holder when calculating calendar
 height.

---
 .../java/com/kizitonwose/calendarview/ui/CalendarAdapter.kt    | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/library/src/main/java/com/kizitonwose/calendarview/ui/CalendarAdapter.kt b/library/src/main/java/com/kizitonwose/calendarview/ui/CalendarAdapter.kt
index fa627118..32a847da 100644
--- a/library/src/main/java/com/kizitonwose/calendarview/ui/CalendarAdapter.kt
+++ b/library/src/main/java/com/kizitonwose/calendarview/ui/CalendarAdapter.kt
@@ -193,7 +193,8 @@ internal class CalendarAdapter(
                         calWrapsHeight = it
                     }
                     if (calWrapsHeight.not()) return // Bug only happens when the CalenderView wraps its height.
-                    val visibleVH = calView.findViewHolderForAdapterPosition(visibleItemPos) as MonthViewHolder
+                    val visibleVH =
+                        calView.findViewHolderForAdapterPosition(visibleItemPos) as? MonthViewHolder ?: return
                     val newHeight = visibleVH.headerView?.height.orZero() +
                         // For some reason `visibleVH.bodyLayout.height` does not give us the updated height.
                         // So we calculate it again by checking the number of visible(non-empty) rows.