How to maximize QSplitter in a QWidget

[tkm]

I'm just guessing, but it sounds to me like you haven't put something in a layout that needs to be. Is the widget that your splitter is governing the central widget of the window or has it been added? Did you add it to a layout?

My splitter has two widgets. Both should be the central. The splitter is added to a layout.
My code as below: (Do note that the code exists in the constructor of a class inheriting a QWidget)

splitter = new QSplitter(Qt::Horizontal);

treeItem = new QTreeView;
listItem = new QListView;
QList<int> sizes;
sizes.append(200);
sizes.append(600);

splitter->addWidget(treeItem);
splitter->addWidget(listItem);
splitter->setSizes(sizes);
splitter->setStretchFactor(0, 1);
splitter->setStretchFactor(1, 1);

QVBoxLayout *layoutMain = new QVBoxLayout;
layoutMain->setContentsMargins(0, 0, 0, 0);
layoutMain->addWidget(splitter);
layoutMain->addStretch();
setLayout(layoutMain);
showMaximized();