[SOLVED] TreeView move row one down causes app crash.



  • I use Qt 5.3.2. I have tree like this:
    @
    QModelIndex()
    |- Item 0
    |- Item 1
    |- Item 2
    |- Item 3
    |- Item 4
    @

    Implemented virtual method:
    @
    bool ViewModel::moveRows(const QModelIndex &sourceParent, int sourceRow, int count,
    const QModelIndex &destinationParent, int destinationChild)
    {
    if(sourceRow < 0 || sourceRow >= rowCount(sourceParent))
    return false;
    if(destinationChild < 0 || destinationChild >= rowCount(destinationParent))
    return false;
    if(sourceRow == destinationChild)
    return false;

    beginMoveRows(sourceParent, sourceRow, sourceRow + count - 1,
                  destinationParent, destinationChild);
    endMoveRows();
    
    return true;
    

    }
    @

    When I move item from 2 to 1 it works, but when I move item form 2 to 3 it crash becouse in qt source return false:
    @
    bool QAbstractItemModelPrivate::allowMove(const QModelIndex &srcParent, int start, int end, const QModelIndex &destinationParent, int destinationStart, Qt::Orientation orientation)
    {
    // Don't move the range within itself.
    if (destinationParent == srcParent)
    return !(destinationStart >= start && destinationStart <= end + 1);
    @

    Example for moving item down:
    @
    bool ViewModel::moveRows(const QModelIndex &sourceParent, int sourceRow, int count, QModelIndex &destinationParent, int destinationChild)

    //with values
    bool ViewModel::moveRows(QModelIndex(), 2, 1, QModelIndex(), 3)
    @

    In critical code where return false but need true:
    @
    return !(destinationStart >= start && destinationStart <= end + 1);

    //with values
    return !( 3 >= 2 && 3 <= 2 + 1 );
    return !( true && true);
    @

    I did some mistake, or it's bug in qt 5.3.2?




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