Scroll Area Added and Set Up but No Scrollbar Appears - c++

Question

I've seen and tried various QT scrollArea solutions over the past 2 days but none of them work for me. Here's my scroll area setup code as it stands in the MainWindow constructor. This builds and runs without error but doesn't do anything. The scrollArea and ui->Contents have already been set up in the form using QTcreator and the needed widgets have been moved into the scrollArea.
ui->scrollArea->installEventFilter(this);
ui->scrollArea->setMouseTracking(true);
ui->scrollArea->setWidget(ui->Contents);
QVBoxLayout *layout = new QVBoxLayout(this);
layout->setSizeConstraint(QLayout::SetMinimumSize);
ui->scrollArea->setLayout(layout);
The last line seems interchangeable with:
layout->addWidget(ui->scrollArea)
but neither one changes the result, which is a fully-functioning application but without the scroll area I need.

Answer 1

I had similar problem which i solved by creating scrollArea and it's contents via code rather than form and only then using setWidget() method. I described the problem in this thread.
In your case code should look something like this:
QScrollArea *scrollArea;
scrollArea = new QScrollArea(this);
scrollArea->installEventFilter(this);
scrollArea->setMouseTracking(true);
scrollArea->setWidget(Contents);//whatever Contents is, i recommend creating it via code
QVBoxLayout *layout = new QVBoxLayout(this);
layout->setSizeConstraint(QLayout::SetMinimumSize);
scrollArea->setLayout(layout);