How to get minimize/restore/close rectangle?

问题

I want to draw some text in the end of menu bar like this

But when the child window is maximized in the MDI project it looks like this

I need to fix this output.
I want to check if the active child is maximized and if it is I want to get minimize/restore/close rectangle to get them total width.
How can I get active child window and how can I get it's rectangle of buttons?

回答1:

// in yourMainWindow.cpp

...

auto child = mdiArea->addSubWindow(yourWidget);
connect(child, &QMdiSubWindow::windowStateChanged, this, &yourMainWindow::yourSlot);

...

void yourMainWindow::yourSlot(Qt::WindowStates oldState, Qt::WindowStates newState)
{
    if (newState.testFlag(Qt::WindowMaximized)) {
        auto child = qobject_cast<QMdiSubWindow *>(sender());
        if (!child)
            return;

        QStyleOptionComplex opt;
        opt.initFrom(child);

        auto size = child->style()->sizeFromContents(QStyle::CT_MdiControls, &opt, QSize(100, 20));
        qDebug() << size;
    }
}

来源：https://stackoverflow.com/questions/34433958/how-to-get-minimize-restore-close-rectangle