Details
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Bug
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Resolution: Unresolved
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Not Evaluated
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None
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Some Release
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None
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Windows XP SP3
Qt 4.5.2
Description
Qt/MFC Migration Framework
Version 2.8
We use QWinWidget to embed our Widget into another Windows application. In one of our use cases the Widget loses the focus. In this case the function focusWidget() of QWinWidget returns null.
This leads to a crash in QWinWidget::focusNextPrevChild(). The first thing that function does is calling focusWidget(). The retrieved pointer is afterward used without checking. To solve this, all you have to do is checking the pointer retrieved from focusWidget.
The following fix solved the problem for us:
bool QWinWidget::focusNextPrevChild(bool next)
{
QWidget *curFocus = focusWidget();
if (0 != curFocus) {
if (!next) {
if (!curFocus->isWindow()) {
QWidget *nextFocus = curFocus->nextInFocusChain();
QWidget *prevFocus = 0;
QWidget *topLevel = 0;
while (nextFocus != curFocus) {
if (nextFocus->focusPolicy() & Qt::TabFocus) {
prevFocus = nextFocus;
topLevel = 0;
} else if (nextFocus->isWindow()) {
topLevel = nextFocus;
}
nextFocus = nextFocus->nextInFocusChain();
}
if (!topLevel) {
return QWidget::focusNextPrevChild(false);
}
}
} else {
QWidget *nextFocus = curFocus;
while (1) {
nextFocus = nextFocus->nextInFocusChain();
if (nextFocus->isWindow())
break;
if (nextFocus->focusPolicy() & Qt::TabFocus) {
return QWidget::focusNextPrevChild(true);
}
}
}
}
::SetFocus(hParent);
return true;
}