Adding custom widgets to QMenuBar

Question

Qt3 used to provide QMenuBar::insertItem with QWidget* parameter. This way any custom widget could be added to menu bar - for example a clock-widget. In Qt4 there is no such overloaded method. What would be the best way to reach the same goal - adding custom widgets to a menu bar? The custom widgets should be integrated in the layout of menu bar. Does anyoune knows the background, why this overload of insertItem was removed in Qt4 API?

Best regards.

Answer 1

there's a QMenuBar::addAction ( QAction * action ) method, to add an arbitrary QAction to the menu bar.
For example, it could be a QWidgetAction, which is a subclass of QAction with an associated QWidget instead of just an icon + text.

Answer 2

Sorry Javier for short comments. Every time I intended to break a line, the comment was submitted :-(

I tried this code in a project created with QtCreator:

class MyWidgetAction : public QWidgetAction
{
public:
    MyWidgetAction( QObject * parent ) :QWidgetAction (  parent )
    {

    }
    void releaseWidget ( QWidget * widget )
    {
        widget->deleteLater();
    }

    QWidget * requestWidget ( QWidget * parent )
    {
        QPushButton *b = new QPushButton( tr("MyWidget"), parent );
        b->show();
        return b;
    }
};

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);    
    QAction *a = new QAction(tr("TestAction"),this); //1
    QWidgetAction * wa = new QWidgetAction(this);    //2
    wa->setDefaultWidget(new QPushButton("Default"));
    MyWidgetAction *mwa = new MyWidgetAction(this);  //3

    ui->menuBar->addAction( a ); //1 - works. TestAction added to menu bar
    ui->menuBar->addAction( wa ); //2 - noop. nothing added to menu bar
    ui->menuBar->addAction( mwa ); //3 - noop. nothing added to menu bar
}

Only adding QAction (1) worked. Neither adding QWidgetAction with default widget not subclassing QWidgetAction gave a result. I've set breakpoints in C-Tor and both virtual functions of MyWidgetAction. Surprisingly, only C-Tor break-point was hit. I've tried on Windows with Open-Source, MinGW version of Qt4.6.3 Could it be a bug in Qt? Thank you very much in advance for any suggestions!

Regards, Valentin Heinitz

Answer 3

I was only able to do this by adding my QMenuBar and custom widget to a new QWidget and using THAT as the menubar:

MenuWidget::MenuWidget(QWidget *parent, Qt::WFlags flags)
    : QMainWindow(parent, flags)
{
    ui.setupUi(this);

    QWidget *w = new QWidget(this);
    QHBoxLayout *layout = new QHBoxLayout(w);

    layout->addWidget(ui.menuBar);

    QLineEdit *edit = new QLineEdit("", w);
    layout->addWidget(edit);

    layout->addStretch(10);

    setMenuWidget(w);
}

This works for Windows, but it doesn't work on the Mac.