Introduce QLayout::indexOf(QLayoutItem *)

This was the missing counter-part to indexOf(QWidget *), which is
sometimes implemented in user code.

Not sure why the original code doesn't use a for-loop and instead accesses
an out-of-bounds element, but I'll preserve the behavior of very old working code.

Change-Id: I7d7fa56b56a4626789774c15c23fdfef41d723e7
Reviewed-by: David Faure <david.faure@kdab.com>
Reviewed-by: Jan Arve Sæther <jan-arve.saether@qt.io>

1 files changed, 20 insertions, 0 deletions

diff --git a/src/widgets/kernel/qlayout.cpp b/src/widgets/kernel/qlayout.cpp
index f3db4f4e2d..64acd8d229 100644
--- a/src/widgets/kernel/qlayout.cpp
+++ b/src/widgets/kernel/qlayout.cpp
@@ -1244,6 +1244,26 @@ int QLayout::indexOf(QWidget *widget) const
 }
 
 /*!
+    \since 5.12
+    Searches for layout item \a layoutItem in this layout (not including child
+    layouts).
+
+    Returns the index of \a layoutItem, or -1 if \a layoutItem is not found.
+*/
+int QLayout::indexOf(QLayoutItem *layoutItem) const
+{
+    int i = 0;
+    QLayoutItem *item = itemAt(i);
+    while (item) {
+        if (item == layoutItem)
+            return i;
+        ++i;
+        item = itemAt(i);
+    }
+    return -1;
+}
+
+/*!
     \enum QLayout::SizeConstraint
 
     The possible values are: