MainWindow::MainWindow() { QMenu *fileMenu = new QMenu(tr("&File")); QAction *quitAction = fileMenu->addAction(tr("E&xit")); quitAction->setShortcut(tr("Ctrl+Q")); menuBar()->addMenu(fileMenu); // For convenient quoting: QTreeView *treeView = new QTreeView(this); treeView->setSelectionMode(QAbstractItemView::ExtendedSelection); treeView->setDragEnabled(true); treeView->setAcceptDrops(true); treeView->setDropIndicatorShown(true); this->treeView = treeView; connect(quitAction, SIGNAL(triggered()), this, SLOT(close())); setupItems(); setCentralWidget(treeView); setWindowTitle(tr("Tree View")); }