I've checked the documentation here and I can't seem to find a method for setting the text of a QTreeWidget's title or header.
Without setting the title QTreeWidget automatically uses the number '1' in my code. An example of what it looks like outputted is below. I'm presuming QTreeWidget has a method for this and I just can't find it.
You're looking for setHeaderLabel.
Note that the documentation says it adds a new column, so if your view already has column 0 with text "1", you may instead have to do the following:
if(QTreeWidgetItem* header = treeWidget->headerItem()) {
header->setText(0, "My Text");
} else {
treeWidget->setHeaderLabel("My Text");
}