设置表头：setHeaderLabels
QTreeView::branch:selected {
background: #BCCFE7;
selection-background-color:#BCCFE7;
}
QTreeView::branch:has-children:!has-siblings:closed,
QTreeView::branch:closed:has-children:has-siblings {
border-image: none;
image: url(:/image/add-line_horizontal.png);
}
QTreeView::branch:open:has-children:!has-siblings,
QTreeView::branch:open:has-children:has-siblings {
border-image: none;
image: url(:/image/add-line_vertical.png);
}