How to show a sub-tree-item in Qt?

Question

Using Qt's model-view framework to represent a tree structure, such as Qt provided simple tree example, the tree view shows the root-tree-item. Any way to show a sub-tree-item, such as a child item of the root?

Answer 1

The documentation for Qt's model/view framework covers this.

In short, these methods determine the structure of your tree:

• QAbstractItemModel::index(), which should return the child indices of a given parent index
• QAbstractItemModel::parent(), which should return the parent index of a given child

Note that if you have a large view, these methods must be fast, because the Qt item views will call them very often.

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If you don't absolutely need to implement your own model , I would also suggest looking at QTreeWidget (instead of QTreeView), which is a much simpler, retained-mode tree view widget. It provides most of the same features with a much easier-to-use (and less error-prone) conceptual model.