解决啦,谢谢,i是int型的,代表你想给第i个item添加子item.
定义一个QModelIndex类的index,代码如下:
int i;
QModelIndex index=ui->treeWidget->model()->index(i,0,QModelIndex());
ui->treeWidget->setCurrentIndex(index);
QTreeWidgetItem* item=new QTreeWidgetItem(ui->treeWidget->currentItem()); //添加子item
item->setText(0,tr("子条目"));