How to compose buttons in QScrollArea?

Question

I'm creating dynamically unknown number of buttons and put them to QScrollArea.

someDialogButton = new QPushButton();
usersDialogs.push_back(someDialogButton);
ui->usersArea->setWidget(someDialogButton);

usersDialogs is QVector<QPushButton*>

usersArea is QScrollArea

But the buttons overlap and can be seen only the last button added. I tried use: setLayout(QLayout* layout) method, but it was useless.

How I can compose the buttons to make all buttons visible?

Answer 1

The Qt documentation says

void QScrollArea::setWidget(QWidget * widget)

Sets the scroll area's widget.

The widget becomes a child of the scroll area, and will be destroyed when the scroll area is deleted or when a new widget is set.

Therefore, whenever you call QScrollArea::setWidget() you overwrite the previous widget. What you need to do is to fill a QWidget with the buttons and then you call QScrollArea::setWidget() on that container widget.

Here's an example, of what your classes constructor could look like:

MainWindow::MainWindow(QWidget *parent) 
    : QWidget(parent)
{
    this->resize( 300, 200 );
    auto * layout = new QVBoxLayout(this);
    auto * scrollArea = new QScrollArea(this);
    scrollArea->setWidgetResizable( true );
    layout->addWidget( scrollArea );
    auto * container = new QWidget();
    scrollArea->setWidget( container );
    layout = new QVBoxLayout(container);
    auto * button1 = new QPushButton( "1", container);
    auto * button2 = new QPushButton( "2", container);
    auto * button3 = new QPushButton( "3", container);
    layout->addWidget( button1 );
    layout->addWidget( button2 );
    layout->addWidget( button3 );
}

For me it gives this: