Qt How to highlight menu? [duplicate] - c++

Question

This question already has answers here:
How to focus menuBar() with Qt
(2 answers)
Closed 4 years ago.
I need to do hide/show main menu function by pressing the Alt key (like in FireFox). I know how to hide and show it, but I can't highlight menu after showing it. I've tried menuBar()->actions()[0].hover(), activateWindow(), setActiveAction(), activate(QAction::Hover), but nothing helps. How can I do it? Maybe I should use WinApi functions instead of Qt?
bool MainWindow::event(QEvent *event){
if (event->type() == QEvent::KeyPress)
{
QKeyEvent *ke = static_cast<QKeyEvent*>(event);
if (ke->key() == Qt::Key_Alt)
{
keyReleaseEvent(ke);
return true;
}
}
return QMainWindow::event(event);
}
Handle Alt
void MainWindow::keyReleaseEvent (QKeyEvent* event)
{
if (event->key() == Qt::Key_Alt){
if (menuBar()->isHidden()){
menuBar()->show();
menuBar()->setFocus(Qt::MenuBarFocusEvent); //here I trying to highlight the menu
}
else{
menuBar()->hide();
{
}
}

Answer 1

Duplicate of How to focus menuBar() with Qt (which I just answered)
Because the answer isn't accepted on the other question, I can't flag this one as a duplicate. Including answer below as well:
I wanted to do the same thing. My solution, complete example, as a gist:
https://gist.github.com/xim/ee56564f425151ea2fa70f730d644873
As it contains a lot of other junk, a minimal example:
class AutoHidingMenuBar : public QMenuBar {
Q_OBJECT
public:
AutoHidingMenuBar() : QMenuBar() {
setMaximumHeight(0);
connect(qApp, &QApplication::focusChanged, this, &AutoHidingMenuBar::focusChanged);
}
private slots:
void focusChanged(QWidget *from, QWidget *to) {
bool inFocus = hasFocus() || isAncestorOf(focus) || hasFocusedChild();
if (inFocus && maximumHeight() == 0) {
auto action = activeAction();
setMaximumHeight(100);
if (action) {
// XXX This is a bit of a hack. We could do
// QCoreApplication::processEvents();
// setActiveAction(action);
// with almost the same effect, but then we *open* the first menu on single alt press...
auto evt = new QMouseEvent(QEvent::MouseMove, actionGeometry(action).center(), Qt::NoButton, Qt::NoButton, Qt::NoModifier);
QCoreApplication::postEvent(this, evt);
}
} else if (!inFocus && maximumHeight() != 0)) {
setMaximumHeight(0);
}
}
private:
bool hasFocusedChild();
};

Answer 2

Try to debug it and see what is happening.
You can do something like:
if (menuBar()->hasFocus())
qDebug() << " I have the focus";
else
qDebug() << " I don't have the focus";
And see if it has the focus but works bad or if it has no focus which I think that is problem... somewhere it is losing it
A little trick that may help you is using:
QTimer::singleShot(0, menuBar(), SLOT(setFocus()));
on your MainWindow::keyReleaseEvent
And last thing... Note that set focus needs a focusPolicy, maybe this helps you.