QWidget::height() of a just-added widget into a layout

Question

How do I get the final height of a widget that was just added to a layout, but because of this, it has not resized to its final size?

Basically I need to do this:

myGridLayout->addWidget ( somewidget, 0, 0, 1, 1 );

QPushButton *b = new QPushButton(somewidget);
b->setGeometry( somewidget->width() - 50,
                somewidget->height()/2 - 150,
                50, 300);

What I want to do is to insert a button (50x300) in the middle of the right edge of the just added widget, but for this I need to know the dimensions of the widget, which I'm not getting correctly because it has not resized to its full size in the layout. Any ideas?

Answer 1

Normally, the content of a layout is calculated right before being displayed. If you need to force it earlier, you can call either QLayout::activate() or QLayout::update(), which redoes or updates the layout for its parent widget.

Answer 2

If I understand you correctly, this should accomplish what you are trying to do without trying to catch the size at the right time. Add a layout to your 'somewidget' and add the button to that.

myGridLayout->addWidget(somewidget, 0, 0, 1, 1 );

QGridLayout *layout = new QGridLayout(somewidget);
QPushButton *button = new QPushButton();
button->setText("button");
button->setMaximumSize(50,300);
button->setMinimumSize(50,300);
button->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
layout->addWidget(button, 0, 0, Qt::AlignVCenter | Qt::AlignRight);