I can't update my items in QAbstractListModel

[Alien]

Hi,
I implemented a class which inherited from QAbstractListModel I don't have any problem with inserting an items or removing them (The ListView will update correctly)the problem is that I can't update the items inside the list my ListView doesn't update whatsoever.

Note:I don't want to remove the item and then insert it again in order to simulate the update behavior.

I would appreciate any ideas

SDK:QT5.9.0
COMPILER:MINGW 32bit on Windows 7

[dheerendra]

Did you get a chance to look at the ObjectList example given in the Qt Installation Example directory ?. It may help you.

[Eeli K]

@Alien What have you tried so far? dataChanged signal?

[Alien]

Dear @dheerendra ,
No where is it I just have a review of AbstractItemModel example

[Alien]

Dear @Eeli-K ,
I just want to update my model so I expect that ListView will be aware of the change, I used

emit dataChanged()

after I've changed model's data with no hope.
When I remove the item and insert it again the item will be updated of course I use some pair functions like ( beginInsertRows,endInsertRows) and (beginRemoveRows,endRemoveRows) , but as you know this is simulate the update behavior(Not a real update).
Extra information:I use QList in my model for keeping data and for updating the items I use replace function of QList .

[Eeli K]

@Alien Can you show the code which actually changes the data and emits dataChanged?

[Alien]

@Eeli-K ok that's my code:

Header File:

class LayerManagerModel : public QAbstractListModel
{
    Q_OBJECT
public:
    LayerManagerModel(QObject *parent = 0);
    ~LayerManagerModel();
    // QAbstractItemModel interface
public:
    int rowCount(const QModelIndex & parent = QModelIndex()) const override;
    bool setData(const QModelIndex &index, const QVariant &value, int role) override;
    QVariant headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const override;
    Qt::ItemFlags flags(const QModelIndex &index) const override;
    QVariant data(const QModelIndex &index, int role=Qt::DisplayRole) const override;
    //    bool insertRows(int row, int count, const QModelIndex &parent=QModelIndex()) override;
    //    bool removeRows(int row, int count, const QModelIndex &parent) override;
    bool removeData(int row);
    QHash<int, QByteArray> roleNames() const override;
    bool addData(LayerInformation* layerInformation);
    void updateVisibility(int index,int visibilitStatus);

private:
    QList<LayerInformation> m_layerInformationList;
    enum LayerManagerModelRoles {
        NameRole = Qt::UserRole + 1,
        VisibleRole,
        DateOfCreationRole,
        DescriptionRole,
        UserNameRole,
        ZOrderRole,
        FilePathRole
    };
};

Update function implementation:

void LayerManagerModel::updateVisibility(int index,int visibilitStatus)
{
/*    
	LayerInformation layerInfo = m_layerInformationList.at(index);
    layerInfo.setIsVisible((visibilitStatus==1)?"YES":"NO");
    beginRemoveRows(QModelIndex(),index,index);
    m_layerInformationList.removeAt(index);
    endRemoveRows();
    beginInsertRows(QModelIndex(),index,index);
    m_layerInformationList.insert(index,layerInfo);
    endInsertRows();
	*/
	LayerInformation layerInfo = m_layerInformationList.at(index);
	layerInfo.setIsVisible((visibilitStatus==1)?"YES":"NO");
    //    m_layerInformationList.replace(index,layerInfo);
    //    setData(qm ,visibilitStatus,VisibleRole);
	
    emit dataChanged(QModelIndex(),QModelIndex());

}

Thanks for your attention

[Eeli K]

@Alien at() is for const reference, you have to use [] if you want to modify the returned item via the reference.

[Eeli K]

@Alien And if your're worried about efficiency you should emit dataChanged(this->index(index),this->index(index)); so that the view doesn't go through all rows.

[Alien]

@Eeli-K ,
Thank you so much that was just because of emit

dataChanged(this->index(index),this->index(index));

I really appreciate your help