Fix pointer mismatch after QList::move() in tooltip example

The tooltip example moves shape items within a QWidget. Shape items are
stored in a QList of objects. When an item is moved, its pointer is
taken from the QList and stored in a member variable. To have the moved
item on the bottom of the list, QList::move() is called. This
operation re-arranges the list objects, and the member variable starts
pointing at a wrong object.

This patch changes the list from a list of objects, to a list of
pointers. Shape items are therefore allocated on the heap.
A destructor is added to free the heap with qDeleteAll.

The example's documentation is adapted accordingly and a snippet for
the destructor is added.

As a drive-by, int is replaced by qsizetype where it was used as an
index of a QList.

Fixes: QTBUG-104781
Pick-to: 6.5 6.2
Change-Id: I9be26fa7954be5f85729d24f166d66980af71801
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

1 files changed, 10 insertions, 6 deletions

diff --git a/examples/widgets/doc/src/tooltips.qdoc b/examples/widgets/doc/src/tooltips.qdoc
index 4712c80851..3af3768f00 100644
--- a/examples/widgets/doc/src/tooltips.qdoc
+++ b/examples/widgets/doc/src/tooltips.qdoc
@@ -124,6 +124,10 @@
     private \c createShapeItem(), \c initialItemPosition() and \c
     initialItemColor() functions.
 
+    \snippet widgets/tooltips/sortingbox.cpp 27
+
+    In the destructor, we delete all shape items.
+
     \snippet widgets/tooltips/sortingbox.cpp 5
 
     QWidget::event() is the main event handler and receives all the
@@ -199,8 +203,9 @@
     If an item covers the position, we store a pointer to that item
     and the event's position. If several of the shape items cover the
     position, we store the pointer to the uppermost item. Finally, we
-    move the shape item to the end of the list, and make a call to the
-    QWidget::update() function to make the item appear on top.
+    move the shape item's pointer to the end of the list, and make
+    a call to the QWidget::update() function to make the item appear
+    on top.
 
     The QWidget::update() function does not cause an immediate
     repaint; instead it schedules a paint event for processing when Qt
@@ -290,10 +295,9 @@
 
     The \c createShapeItem() function creates a single shape item. It
     sets the path, tooltip, position and color, using the item's own
-    functions. In the end, the function appends the new item to the
-    list of shape items, and calls the QWidget::update() function to
-    make it appear with the other items within the \c SortingBox
-    widget.
+    functions. In the end, the function appends the new item's pointer
+    to the list of shape items, and calls QWidget::update() to make
+    it appear with the other items within the \c SortingBox widget.
 
     \snippet widgets/tooltips/sortingbox.cpp 22