Popup Menu not closing after clicking custom widget

[stefanadelbert]

I have a QMenu that contains one QActionWidget. The QActionWidget contains a custom QWidget (CSpinBoxWidget), which comprises a QSpinBox and a custom QPushButton (CTitleButton).

When the CTitleButton is clicked I would like the QMenu to close.

I read here that I will most likely need to do something with the handling of mouseReleaseEvent. I decided to use a QPushButton, but I did try with a QToolButton and couldn't get it working.

When the CTitleButton is clicked, CTitleButton::mouseReleaseEvent gets called. Then the event is passed to the parent of the CTitleButton, which is the CSpinBoxWidget.

Note: I tried connecting CSpinBoxWidget::titleClicked [signal] to QActionWidget::trigger [slot], but this didn't help.

class CTitleButton : public QPushButton
{
    Q_OBJECT
 
public:
    CTitleButton(QWidget* parent = 0) : QPushButton(parent) {}
    void mouseReleaseEvent(QMouseEvent* event) {
        QPushButton::mouseReleaseEvent(event);
        QWidget::mouseReleaseEvent(event);
    }   
};
 
class CSpinBoxWidget : public QWidget
{
 
    Q_OBJECT
 
public:
    CSpinBoxWidget(const QString& t, QWidget* parent = 0) :
            QWidget(parent)
    {
        value = new QSpinBox(parent);
        value->setContextMenuPolicy(Qt::NoContextMenu);
 
        title = new CTitleButton(parent);
        title->setText(t);
 
        QHBoxLayout* hLayout = new QHBoxLayout(parent);
        hLayout->addWidget(title);
        hLayout->addWidget(value);
        hLayout->setSpacing(2);
        hLayout->setMargin(2);
        setLayout(hLayout);
 
        // When the title button is clicked
        connect(title, SIGNAL(clicked()),
            this, SIGNAL(titleClicked()));
    }
    ~CSpinBoxWidget() {}
 
public:
    int Value() { return value->value(); }
    void SetValue(int val) { value->setValue(val); }
    void SetMinimum(int min) {
        value->setMinimum(min);
    }
    void SetMaximum(int max) {
        value->setMaximum(max);    
    }
 
signals:
    void titleClicked();
 
private:
    void mouseReleaseEvent(QMouseEvent* e) {
        QWidget::mouseReleaseEvent(e);
    }
 
private:
    QSpinBox* value;
    QPushButton* title;
};

class CTitleButton : public QPushButton
{
    Q_OBJECT

public:
    CTitleButton(QWidget* parent = 0) : QPushButton(parent) {}
    void mouseReleaseEvent(QMouseEvent* event) {
        QPushButton::mouseReleaseEvent(event);
        QWidget::mouseReleaseEvent(event);
    }   
};

class CSpinBoxWidget : public QWidget
{
    
    Q_OBJECT

public:
    CSpinBoxWidget(const QString& t, QWidget* parent = 0) :
            QWidget(parent)
    {
        value = new QSpinBox(parent);
        value->setContextMenuPolicy(Qt::NoContextMenu);

        title = new CTitleButton(parent);
        title->setText(t);

        QHBoxLayout* hLayout = new QHBoxLayout(parent);
        hLayout->addWidget(title);
        hLayout->addWidget(value);
        hLayout->setSpacing(2);
        hLayout->setMargin(2);
        setLayout(hLayout);

        // When the title button is clicked
        connect(title, SIGNAL(clicked()),
            this, SIGNAL(titleClicked()));
    }
    ~CSpinBoxWidget() {}

public:
    int Value() { return value->value(); }
    void SetValue(int val) { value->setValue(val); }
    void SetMinimum(int min) {
        value->setMinimum(min);
    }
    void SetMaximum(int max) {
        value->setMaximum(max);    
    }

signals:
    void titleClicked();

private:
    void mouseReleaseEvent(QMouseEvent* e) {
        QWidget::mouseReleaseEvent(e);
    }

private:
    QSpinBox* value;
    QPushButton* title;
};

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But I don't understand how the event handling is supposed to work. When I create the QMenu, QWidgetAction and CSpinBox widget, does it matter who is whose parent as far as the event handling goes?

"QWidget::mouseReleaseEvent(event);" in CTitleButton::mouseReleaseEvent(QMouseEvent* event) ends up calling "event->ignore();", so does nothing really.

There is a documentation snippet in qwidgetaction.cpp that reads:

Note that it is up to the widget to activate the action, for example by reimplementing mouse event handlers and calling QAction::trigger().

But this doesn't make sense to me. How does the widget activate the action? Which mouseReleaseEvent functions need to be reimplemented? Who needs to call QAction::trigger (could only be derived QWidgetAction or QMenu)?

Any ideas?

Stefan

[stefanadelbert]

QMenu is receiving the mouseReleaseEvent, but is doing nothing with it.

d->mouseDown != this resolves to true so

d->mouseDown = 0;
return;

d->mouseDown = 0;
return;

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is being run.

Here is QMenu::mouseReleaseEvent (see qmenu.cpp):

void QMenu::mouseReleaseEvent(QMouseEvent *e)
{
    Q_D(QMenu);
    if (d->aboutToHide || d->mouseEventTaken(e))
        return;
    if(d->mouseDown != this) {
        d->mouseDown = 0;
        return;
    }
 
    d->mouseDown = 0;
    d->setSyncAction();
    QAction *action = d->actionAt(e->pos());
 
    if (action && action == d->currentAction) {
        if (action->menu())
            action->menu()->d_func()->setFirstActionActive();
        else {
#if defined(Q_WS_WIN)
            //On Windows only context menus can be activated with the right button
            if (e->button() == Qt::LeftButton || d->topCausedWidget() == 0)
#endif
                d->activateAction(action, QAction::Trigger);
        }
    } else if (d->hasMouseMoved(e->globalPos())) {
        d->hideUpToMenuBar();
    }
}

void QMenu::mouseReleaseEvent(QMouseEvent *e)
{
    Q_D(QMenu);
    if (d->aboutToHide || d->mouseEventTaken(e))
        return;
    if(d->mouseDown != this) {
        d->mouseDown = 0;
        return;
    }

    d->mouseDown = 0;
    d->setSyncAction();
    QAction *action = d->actionAt(e->pos());

    if (action && action == d->currentAction) {
        if (action->menu())
            action->menu()->d_func()->setFirstActionActive();
        else {
#if defined(Q_WS_WIN)
            //On Windows only context menus can be activated with the right button
            if (e->button() == Qt::LeftButton || d->topCausedWidget() == 0)
#endif
                d->activateAction(action, QAction::Trigger);
        }
    } else if (d->hasMouseMoved(e->globalPos())) {
        d->hideUpToMenuBar();
    }
}

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Does this mean that the menu thinks that it wasn't actually clicked? What does d->mouseDown actually represent?

[norobro]

A simplistic look at this, but will connecting the titleClicked() signal to the QMenu::hide() slot not work?

[stefanadelbert]

Sometimes simple is best. I'll give that a try and I reckon that it'll do that trick.

EDIT: Of course that works! Those were a few hours of my life that I won't get back.

@norobro: thanks

EDIT: I've been able to remove a fair amount of code now, notably the derived QPushButton with reimplemented mouseReleaseEvent. It would be nice to use the event/action framework as intended, but...

[norobro]

Glad I could help! You were way over my head delving into the event/action framework. I'm the two S'es of the K.I.S.S. principle.

[stefanadelbert]

Any idea how I mark a thread as solved or closed?