How to create QToolBar in QWidget? - c++

Question

I am trying to add a QToolBar in a QWidget. But I want its functionality to work as if it was a QMainWindow.
Apparently I can not create QToolBar in a QWidget, and using setAllowedAreas does not work with QWidget : it only works with QMainWindow. Also, my QWidget is in a QMainWindow.
How can I create a QToolBar for my widget?

Answer 1

The allowedAreas property only works when the toolbar is the child of a QMainWindow. You can add the toolbar to a layout, but it won't be movable by the user. You can still relocate it programmatically, however.
To add it to a layout for a fictional class inheriting QWidget:
void SomeWidget::setupWidgetUi()
{
toolLayout = new QBoxLayout(QBoxLayout::TopToBottom, this);
//set margins to zero so the toolbar touches the widget's edges
toolLayout->setContentsMargins(0, 0, 0, 0);
toolbar = new QToolBar;
toolLayout->addWidget(toolbar);
//use a different layout for the contents so it has normal margins
contentsLayout = new ...
toolLayout->addLayout(contentsLayout);
//more initialization here
}
Changing the toolbar's orientation requires the additional step of calling setDirection on the toolbarLayout, e.g.:
toolbar->setOrientation(Qt::Vertical);
toolbarLayout->setDirection(QBoxLayout::LeftToRight);
//the toolbar is now on the left side of the widget, oriented vertically

Answer 2

QToolBar is a widget. That's why, you can add a QToolBar to any other widget by calling addWidget for layout or by setting the QToolBar parent to your widget.
As you can see in documentation of QToolBar setAllowedAreas method:
This property holds areas where the toolbar may be placed.
The default is Qt::AllToolBarAreas.
This property only makes sense if the toolbar is in a QMainWindow.
That's why it is impossible to use setAllowedAreas if toolbar is not in QMainWindow.

Answer 3

As far as I know, the only way to properly use the toolbar is with the QMainWindow.
If you want to use the full functionality of the toolbar, create a mainwindow with the window flag Widget. This way you can add it inside some other widget without having it displayed as a new window:
class MyWidget : QMainWindow
{
public:
MyWidget(QWidget *parent);
//...
void addToolbar(QToolBar *toolbar);
private:
QMainWindow *subMW;
}
MyWidget::MyWidget(QWidget *parent)
QMainWindow(parent)
{
subMW = new QMainWindow(this, Qt::Widget);//this is the important part. You will have a mainwindow inside your mainwindow
setCentralWidget(QWidget *parent);
}
void MyWidget::addToolbar(QToolBar *toolbar)
{
subMW->addToolBar(toolbar);
}