QScrollArea does not add in scrollbars

I have to dynamically create push buttons depending on user inputs, therefore if the user gives a large input number, the widget containing the push buttons has to have the ability to scroll up and down.

For this reason, I am using QScrollArea. I generate the template in Qt designer and the UIC generates the code for me, after which I add in my part which should handle dynamic creation of push buttons. However, I can not seem to get the vertical scroll bars to appear. Here is the relevant part of the code.

verticalWidget = new QWidget(FWHMWorkflowDialog);
verticalWidget->setObjectName(QString::fromUtf8("verticalWidget"));
verticalWidget->setMinimumSize(QSize(150, 0));
verticalWidget->setMaximumSize(QSize(150, 16777215));
verticalLayout_5 = new QVBoxLayout(verticalWidget);
verticalLayout_5->setObjectName(QString::fromUtf8("verticalLayout_5"));
scrollArea = new QScrollArea(verticalWidget);
scrollArea->setObjectName(QString::fromUtf8("scrollArea"));
scrollArea->setMaximumSize(QSize(150, 16777215));
scrollArea->setWidgetResizable(true);
scrollAreaWidgetContents = new QWidget();
scrollAreaWidgetContents->setObjectName(QString::fromUtf8("scrollAreaWidgetContents"));
scrollAreaWidgetContents->setGeometry(QRect(0, 0, 130, 432));

numberOfSlices = numberSlices;
for (int i = 0; i < numberOfSlices; i++)
{
    QWidget *horizontalWidget = new QWidget(scrollAreaWidgetContents);
    horizontalWidget->setMaximumSize(150,40);
    horizontalWidget->setGeometry(QRect(0, i*40, 150, 40));
    hWidgetList.push_back(horizontalWidget);
    
    QHBoxLayout *hLayout = new QHBoxLayout(horizontalWidget);
    hLayoutList.push_back(hLayout);
    hLayout->setSizeConstraint(QLayout::SetMinimumSize);
    hLayout->setContentsMargins(-1, 1, -1, 1);
    
    QPushButton *pushButton = new QPushButton(horizontalWidget);
    pushButtonList.push_back(pushButton);
    QString temp = QString("m_sliceButton").arg(i);
    pushButtonList[i]->setObjectName(temp);
    pushButtonList[i]->setGeometry(QRect(10, 20+i*40, 98, 27));
    hLayout->addWidget(pushButton);
    
    QCheckBox *checkBox = new QCheckBox(horizontalWidget);
    checkBoxList.push_back(checkBox);
    temp =  QString("m_checkBox").arg(i);
    checkBoxList[i]->setObjectName(temp);
    checkBoxList[i]->setEnabled(true);
    checkBoxList[i]->setGeometry(QRect(110, 20+i*40, 21, 22));
    
    hLayout->addWidget(checkBox);
    
}

scrollArea->setWidget(scrollAreaWidgetContents);
//scrollArea->setWidgetResizable(true);
   
verticalLayout_5->addWidget(scrollArea);

The output window always looks like the following.

In this example the input by the user is 25, however, you can see that the 21st button is cut off and 4 other buttons are not visible.

The size window problem occurring after scroll functionality started working.

You need to add your horizontalWidget to a vertical widget like so:

QVBoxLayout* vLayout = new QVBoxLayout();

for (int i = 0; i < numberOfSlices; i++)
{
    QWidget *horizontalWidget = new QWidget();
    vLayout->addWidget(horizontalWidget);
    ....
}
scrollAreaWidgetContents->setLayout(vLayout);

You second problem looks like it comes from this line:

scrollArea = new QScrollArea(verticalWidget);

You're adding scrollArea directly to verticalWidget, but to get it to lay out the way you want you need to put it in a layout. Try the following instead:

QVBoxLayout* l = new QVBoxLayout();
l->addWidget(sliceLabel); // or whatever you call it
l->addWidget(scrollArea);
l->addWidget(clearButton); // again, your name here
verticalWidget->setLayout(l);