How to loop over QAbstractItemView indexes?

I want to fire QAbstractItemView::doubleClicked slot programaticaly for an item that has specific text. I want to do this using QAbstractItemView class and not it's implementations if possible.

This task boils down to looping over items and comparing strings. But I cannot find any method that would give me all QModelIndexes. The only method that gives any QModelIndex without parameters is QAbstractItemView::rootIndex. But when I look into QModelIndex docs, I again cannot see a way to access it's children and siblings.

So how to access all QModelIndexes in QAbstractItemView?

Solution

The indexes are provided by the model, not by the view. The view provides the rootIndex() to indicate what node in the model it considers as root; it might be an invalid index. Otherwise it has nothing to do with the data. You have to traverse the model itself - you can get it from view->model().

Here's a depth-first walk through a model:

void iterate(const QModelIndex & index, const QAbstractItemModel * model,
             const std::function<void(const QModelIndex&, int)> & fun,
             int depth = 0)
{
    if (index.isValid())
        fun(index, depth);
    if ((index.flags() & Qt::ItemNeverHasChildren) || !model->hasChildren(index)) return;
    auto rows = model->rowCount(index);
    auto cols = model->columnCount(index);
    for (int i = 0; i < rows; ++i)
        for (int j = 0; j < cols; ++j)
            iterate(model->index(i, j, index), model, fun, depth+1);
}

The functor fun gets invoked for every item in the model, starting at root and going in depth-row-column order.

E.g.

void dumpData(QAbstractItemView * view) {
    iterate(view->rootIndex(), view->model(), [](const QModelIndex & idx, int depth){
        qDebug() << depth << ":" << idx.row() << "," << idx.column() << "=" << idx.data();
    });
}