Qt QGraphicsView: Displaying QGraphicsView inside a tab

Question

I will describe my issue.

I have a class for tab, which looks approximately like this:

class Tab : public QWidget
{
public:
  Tab();
   ...
private:
   ...
  QGraphicsView *view;
   ...
};

In Tab() I create the view . Now in my main window I would like to have a QTabWidget , which contains some tabs, where each tab displays a QGraphicsView . It looks approximately like this:

class MainWindow : QMainWindow
{
public:
  MainWindow();
   ...
private:
   ...
  QTabWidget *tabWidget;
   ...
};

and

MainWindow::MainWindow()
{
  tabWidget = new QTabWidget(this);
  tabWidget->addTab(new Tab, tr("tab 1"));
  tabWidget->addTab(new Tab, tr("tab 2"));

  setCentralWidget(tabWidget);
}

This doesn't display the QGraphicsView s in the tabs. To make the QGraphicsView s visible, I would have to write something like this:

MainWindow::MainWindow()
{
  tabWidget = new QTabWidget(this);
  tab1 = new Tab;
  tab2 = new Tab;
  tabWidget->addTab(tab1->view, tr("tab 1"));
  tabWidget->addTab(tab2->view, tr("tab 2"));

  setCentralWidget(tabWidget);
}

and view would have to be public in the class Tab , which really looks bad. The class Tab has some private functions, which are used to construct view and I don't want view to be public in Tab .

How to get around this?

I was thinking of creating a class, which inherits from QGraphicsView and adding my own functions, but I'm not quite sure how to do this so that it works for me.

Thank you for your answers and comments.

Answer 1

It's most likely because Tab doesn't have a layout (or you even have not added view as a child of Tab widget). You didn't show Tab constructor, so I can't know for sure.

If a tab can contain only a view, then you need to derive Tab class from QGraphicsView instead of QWidget . Additional view class member should be removed, and you can use Tab objects as if it would be QGraphicsView objects.

If a tab can contain other widgets, then you should add a layout to your Tab object and add the view and other children to this layout. Example:

Tab::Tab() {
  QVBoxLayout* main_layout = new QVBoxLayout(this);
  view = new QGraphicsView();
  main_layout->addWidget(view);
}