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Thread: Subclassing QSortFilterProxyModel with lazy population of items

  1. #1

    Default Subclassing QSortFilterProxyModel with lazy population of items

    I'm creating a sortable/filterable tree model displaying DBus services/nodes.
    My code is based on the code used in qdbusviewer, and everything worked fine, until I started implementing lazy population of items (using hasChildren, canFetchMore and fetchMore).
    My base model (DBusModel) works like a charm, but the accompanying proxy model (DBusSortFilterModel) started behaving very strange.
    Sorting seems to work fine, Filtering seems to work fine, but when I expand any item, the whole view gets messed up (items just disappear!!).
    See attached screenshots...

    At the moment my implementation does something like this:
    Qt Code:
    1. bool DBusSortFilterProxyModel::filterAcceptsRow(int sourceRow, const QModelIndex& sourceParent) const
    2. {
    3. // ...
    4. }
    5. bool DBusSortFilterProxyModel::hasChildren(const QModelIndex& parent) const
    6. {
    7. return sourceModel()->hasChildren(mapToSource(parent));
    8. }
    9. bool DBusSortFilterProxyModel::canFetchMore(const QModelIndex& parent) const
    10. {
    11. return sourceModel()->canFetchMore(mapToSource(parent));
    12. }
    13. void DBusSortFilterProxyModel::fetchMore(const QModelIndex& parent)
    14. {
    15. return sourceModel()->fetchMore(mapToSource(parent));
    16. }
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    Probably I'm just overlooking something, or didn't implement some required functionality for this to work. But what?
    Anybody has some experience with this?
    Attached Images Attached Images
    Last edited by sokopok; 4th August 2009 at 14:08. Reason: updated contents

  2. #2
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    Default Re: Subclassing QSortFilterProxyModel with lazy population of items

    Why are you reimplementing the sort filter proxy model? Why isn't implementing lazy population in the source model enough?
    Your biological and technological distinctiveness will be added to our own. Resistance is futile.

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