QWindowsXP/VistaStyle: Fix detection of item view delegate line edits.

The old code tried to check the 2nd parent for inheritance from
QAbstractItemView. This also triggers for line edits on a QDialog parented
on the item view. Introduce convenience function that checks for
top levels in the chain.

Task-number: QTBUG-37504

Change-Id: I932f8efdb4764e9b1eea84c802bf7e8718338e1d
Reviewed-by: J-P Nurmi <jpnurmi@digia.com>
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>

1 files changed, 14 insertions, 7 deletions

diff --git a/src/widgets/styles/qwindowsxpstyle.cpp b/src/widgets/styles/qwindowsxpstyle.cpp
index 63ed3ef7c8..e694eb4e7e 100644
--- a/src/widgets/styles/qwindowsxpstyle.cpp
+++ b/src/widgets/styles/qwindowsxpstyle.cpp
@@ -346,6 +346,19 @@ QString QWindowsXPStylePrivate::themeName(int theme)
            QString();
 }
 
+bool QWindowsXPStylePrivate::isItemViewDelegateLineEdit(const QWidget *widget)
+{
+    if (!widget)
+        return false;
+    const QWidget *parent1 = widget->parentWidget();
+    // Exlude dialogs or other toplevels parented on item views.
+    if (!parent1 || parent1->isWindow())
+        return false;
+    const QWidget *parent2 = parent1->parentWidget();
+    return parent2 && widget->inherits("QLineEdit")
+        && parent2->inherits("QAbstractItemView");
+}
+
 /*! \internal
     This function will always return a valid window handle, and might
     create a limbo widget to do so.
@@ -1548,13 +1561,7 @@ case PE_Frame:
     }
     case PE_FrameLineEdit: {
         // we try to check if this lineedit is a delegate on a QAbstractItemView-derived class.
-        QWidget *parentWidget = 0;
-        if (widget)
-            parentWidget = widget->parentWidget();
-        if (parentWidget)
-            parentWidget = parentWidget->parentWidget();
-        if (widget && widget->inherits("QLineEdit")
-            && parentWidget && parentWidget->inherits("QAbstractItemView")) {
+        if (QWindowsXPStylePrivate::isItemViewDelegateLineEdit(widget)) {
             QPen oldPen = p->pen();
             // Inner white border
             p->setPen(QPen(option->palette.base().color(), 1));