[Solved] Scroll Area Size

sting

I am attempting to get a scroll area to work and have spent way more time then I have. It is probably easy, I am fairly new here. I made a simple example that I can't make work so I removed the complicated code:

@
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
{
// Create QScrollArea and make it the CentralWidget
QScrollArea *scrollArea = new QScrollArea(this);
setCentralWidget(scrollArea);

// Set scroll bar policy
scrollArea->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
scrollArea->setVerticalScrollBarPolicy(Qt::ScrollBarAsNeeded);
//scrollArea->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOn);

// create a horizontal layout for the scroll area
QHBoxLayout *channelLayout = new QHBoxLayout;
scrollArea->setLayout(channelLayout);

// Add 4 colums to the scrollArea
for (int i = 0; i < 4; i++){
    QGroupBox *channelGroup = new QGroupBox();
    QVBoxLayout *groupLayout = new QVBoxLayout(channelGroup);
    channelLayout->addWidget(channelGroup);
    groupLayout->setSizeConstraint( QLayout::SetFixedSize );
    for (int j = 0; j < 20; j++){
        QLabel *waveLabel = new QLabel("Wave: ");
        groupLayout->addWidget(waveLabel);
    }
}

}
@

p3c0

Hi,

Two things that i would like to mention is you setWidgetResizable to true and setMinimumSize for the content widget of ScrollArea greater than the frame of ScrollArea then only the ScrollBars get enabled.
I modified you example which will explain it
@
QScrollArea *scrollArea = new QScrollArea(this);
setCentralWidget(scrollArea);

scrollArea->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
scrollArea->setVerticalScrollBarPolicy(Qt::ScrollBarAsNeeded);
scrollArea->setWidgetResizable(true);

QWidget m_view = new QWidget();
m_view->setContentsMargins(0,0,0,0);
m_view->setMinimumSize(0,10050);

QVBoxLayout *vb = new QVBoxLayout;
m_view->setLayout(vb);

scrollArea->setWidget(m_view);

for(int i=0;i<100;i++) {
QLabel *waveLabel = new QLabel("Wave: "+QString::number(i),m_view);
vb->addWidget(waveLabel);
}
@

sting

Thank you for your help. I took what you posted and put it back into my application and came up with this:

@MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
{
// Create QScrollArea and make it the CentralWidget
QScrollArea *scrollArea = new QScrollArea(this);
setCentralWidget(scrollArea);

// Set scroll bar policy
scrollArea->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
scrollArea->setVerticalScrollBarPolicy(Qt::ScrollBarAsNeeded);
//scrollArea->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOn);

QWidget *clientArea = new QWidget();
clientArea->setContentsMargins(0,0,0,0);

//clientArea->setMinimumSize(0,100*50);

scrollArea->setWidget(clientArea);

// create a horizontal layout for the scroll area
QHBoxLayout *channelLayout = new QHBoxLayout;
channelLayout->setSizeConstraint( QLayout::SetFixedSize );
clientArea->setLayout(channelLayout);

// Add 4 colums to the scrollArea
for (int i = 0; i < 4; i++){
    QGroupBox *channelGroup = new QGroupBox();
    QVBoxLayout *groupLayout = new QVBoxLayout(channelGroup);
    channelLayout->addWidget(channelGroup);
    for (int j = 0; j < 20; j++){
        QLabel *waveLabel = new QLabel("Wave: ");
        groupLayout->addWidget(waveLabel);
    }
}

}
@

I found that the call to setMinimumSize() on the widget for the ScrollArea was not necessary. Is this going to be a problem later on?

I had to call channelLayout->setSizeConstraint( QLayout::SetFixedSize ); to keep the label added to groupLayout from being scalled to fit without scrollbars.

I have learned that the scrollArea needs a widget and not a layout full of widgets to operate correctly. Thank you