problems sorting QAbstractItemModel without QSortFilterProxyModel

[mhennings]

This thread is 6 years old but appears in Google, so I'll hint to the probable solution for future readers.

If you move items the way you do it, you will invalidate your view's internal persistentModelIndices for selected items, current item etc. Next time such a persistent index will be fed to your model's data() function, it will segfault.

For sorting / rearranging items you need to either

beginResetModel();
sortItems();
endResetModel();

beginResetModel();
sortItems();
endResetModel();

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or

for(row in all items) {
    toRow = sortRow(row); // or whatever
    beginMoveRows(row, toRow);
    moveItem(row, toRow);
    endMoveRows();
}

for(row in all items) {
    toRow = sortRow(row); // or whatever
    beginMoveRows(row, toRow);
    moveItem(row, toRow);
    endMoveRows();
}

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