From 4ebb387946b06b434847a11a846dd9fcb46cc1ce Mon Sep 17 00:00:00 2001
From: zeljko <zeljko@lazarus-ide.org>
Date: Sun, 31 Dec 2017 00:37:50 +0000
Subject: [PATCH] Qt: fixed crash with checkable listview when item is deleted
 inside OnItemChecked event. issue #32869

git-svn-id: trunk@56888 -
---
 lcl/interfaces/qt/qtwidgets.pas | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/lcl/interfaces/qt/qtwidgets.pas b/lcl/interfaces/qt/qtwidgets.pas
index 4d3de192b3..e35857d780 100644
--- a/lcl/interfaces/qt/qtwidgets.pas
+++ b/lcl/interfaces/qt/qtwidgets.pas
@@ -12827,8 +12827,9 @@ begin
         else
           SetItemLastCheckStateInternal(AItem, QtUnChecked);
 
-        SendMessage(AItem);
+        // if AItem is deleted in mouse event FDelayedCheckItem becomes nil and that's fine. issue #32869
         FDelayedCheckItem := AItem;
+        SendMessage(AItem);
       end;
     end;
   end else
@@ -12839,6 +12840,8 @@ begin
       SetItemLastCheckStateInternal(FDelayedCheckItem, QListWidgetItem_checkState(FDelayedCheckItem));
       SendMessage(FDelayedCheckItem);
     end;
+    if FDelayedCheckItem = nil then // issue #32869
+      exit;
     FDelayedCheckItem := nil;
     SetItemLastCheckStateInternal(AItem, QListWidgetItem_checkState(AItem));
     SendMessage(AItem);
@@ -13756,6 +13759,8 @@ begin
     if (getSelectionMode = QAbstractItemViewSingleSelection) then
       setCurrentRow(-1);
   Item := QListWidget_takeitem(QListWidgetH(Widget), AIndex);
+  if FDelayedCheckItem = Item then
+    FDelayedCheckItem := nil;
   QListWidgetItem_destroy(Item);
 end;
 
@@ -14466,8 +14471,9 @@ begin
         else
           SetItemLastCheckStateInternal(AItem, QtUnChecked);
 
-        SendMessage(AItem);
+        // if AItem is deleted in mouse event FDelayedCheckItem becomes nil and that's fine. issue #32869
         FDelayedCheckItem := AItem;
+        SendMessage(AItem);
       end;
     end;
   end else
@@ -14478,6 +14484,8 @@ begin
       SetItemLastCheckStateInternal(FDelayedCheckItem, QTreeWidgetItem_checkState(FDelayedCheckItem, 0));
       SendMessage(FDelayedCheckItem);
     end;
+    if FDelayedCheckItem = nil then // issue #32869
+      exit;
     FDelayedCheckItem := nil;
     SetItemLastCheckStateInternal(AItem, QTreeWidgetItem_checkState(AItem, 0));
     SendMessage(AItem);
@@ -15001,6 +15009,8 @@ begin
     Index := -1;
   if Index <> -1 then
     FSelection.Remove(Item);
+  if FDelayedCheckItem = Item then
+    FDelayedCheckItem := nil;
   Item := takeTopLevelItem(AIndex);
   if Item <> nil then
     QTreeWidgetItem_destroy(Item);