Cannot display a tree (QTreeView) inside a QWidget placed inside another QWidget - c++

Question

I have a problem with a QWidget that contains a tree (QTreeView): I can display it if it is created as a widget on its own, and I cannot do the same if it is a subwidget of another higher level widget. In this second case, what I get is an empty widget without the tree.
This works:
QApplication testApp(argc, argv);
MyTree myTree;
testApp.exec();
This does not work:
class MainWindow : public QMainWindow
{
Q_OBJECT
QSplitter *spl1, *spl2;
QMdiArea *mdiArea;
QTableWidget *other;
public:
MainWindow();
void LoadTree();
MyTree *myTree;
};
MainWindow::MainWindow(QWidget *_parent)
: QMainWindow(_parent), myTree(0)
{
mdiArea = new QMdiArea;
other = new QTableWidget;
spl1 = new QSplitter(Qt::Vertical, this);
spl1->addWidget(mdiArea);
spl1->addWidget(other);
LoadTree();
spl2 = new QSplitter(Qt::Horizontal, this);
spl2->addWidget(myTree);
spl2->addWidget(spl1);
setCentralWidget(spl2);
}
void MainWindow::LoadTree()
{
myTree = new MyTree(this);
}
Here is the code common to the two cases (which should be OK):
class MyTree : public QWidget
{
Q_OBJECT
public:
explicit MyTree(QWidget *_parent = 0);
int RefreshTree();
private slots:
void HandleTreeWidgetEvent(QModelIndex);
private:
QWidget *parent;
QTreeView *pjrTree;
QTreeView *GetNewTree();
};
MyTree::MyTree(QWidget *_parent) :
QWidget(_parent),
parent(_parent)
{
pjrTree = GetNewTree();
if(pjrTree) {
if(parent == 0)
pjrTree->show();
}
else {
// Never gets here
}
}
QTreeView* MyTree::GetNewTree()
{
QFileSystemModel *model = new QFileSystemModel;
model->setReadOnly(true);
model->setRootPath("/my/path/");
QTreeView* pjrTree = new QTreeView;
pjrTree->setModel(model);
pjrTree->setRootIndex(model->index("/my/path/"));
QModelIndex index;
index = model->index(4, 1); // temp values - no effect
return pjrTree;
}

Answer 1

Is the tree view the only widget that does not display? I would suggest passing the splitter it will be contained in as the parent, rather than the main window, when you instantiate the tree.

Answer 2

Deriving the class MyTree from QTreeView, instead of having a pointer to QTreeView as a member variable, fixed my problem.