QVariantMap in a QAbstractListModel and C++/QML

[arctik]

hello, I'm using a QAbstractListModel that contains a QVariantMap (m_map)

class CItem
{
public:
    CItem(const QString &name, const QString &url);

    QString name() const;
    QString url() const;
    QVariantMap map() const;

    void setName(const QString& name);
    void setUrl(const QString& url);
    void setMap(const QVariantMap& map);

private:
    QString m_name;
    QString m_url;
    QVariantMap m_map;
};

class CItemModel : public QAbstractListModel
{
    Q_OBJECT
public:
    enum ItemRoles {
        NameRole = Qt::UserRole + 1,
        UrlRole,
        MapRole
    };

    CItemModel(QObject *parent = 0);

    void addItem(const CItem &CItem);
    int rowCount(const QModelIndex & parent = QModelIndex()) const;
    QVariant data(const QModelIndex & index, int role = Qt::DisplayRole) const;
    bool setData(const QModelIndex &index, const QVariant &value, int role = Qt::EditRole);



protected:
    QHash<int, QByteArray> roleNames() const;
private:
    QList<CItem> m_Items;

signals:

};

and I want to visualize and modify all the datas QML like that:

    ListView {
        id: listView
        model : itemModel
        delegate:
            ItemDelegate {
                id: root
                contentItem: ColumnLayout {
                    RowLayout {
                        id: rowLayout
                        ColumnLayout {
                            id: columnLayout
                            Label {
                                id: text1
                                text: model.name
                            }
                            Label {
                                id: text2
                                text: model.url
                            }
                            Label {
                                id: text3
                                text: model.map["test1"] // it works
                            }

                           // did not work
                           Repeater{
                                model: map
                               Text { text: model.map["test1"]}
                            }

no problem with model.name and model.url. (text3 is ok too) but I cant' display all data of my qVariantMap and modify it
is it possible? can you explain me the best approach, please ?

[oria66]

@arctik Hi. The first I notice is that the Repeater does not work with Javascript Objects (Conversion of QVariantMap from C++ side to QML side). Repeater component works with ListModels.

So, maybe there is a better approach, but one way is:

1. Declare an empty LisModel in your qml file.
2. Load or your QVariantMap (JS Object) into ListModel created for that purpose. Automatically, your repeater is going to load the data.
3. In order to modify your QVariantMap, any changes that you do in the ListModel, you are going to call a function that will load data from the ListModel to QVariantMap property from your original model again.

Seems complex and some kind tricky but you can test it.

[jeremy_k]

I suspect the problem is that an object isn't one of the options for a Repeater model.

https://doc.qt.io/qt-6/qml-qtquick-repeater.html#model-prop

This property can be set to any of the supported data models:

• A number that indicates the number of delegates to be created by the repeater
• A model (e.g. a ListModel item, or a QAbstractItemModel subclass)
• A string list
• An object list

Using object.keys() or object.values() to create a string list might work.

[arctik]

@jeremy_k @oria66 Thanks for your answers, i am looking to go in this direction. one more question: if I change the QVariantMap to a QlistModel, will it be easier? what I don't understand is how to handle nested lists in lists with C ++ / Qml. it is however a case which must happen often, or I miss a point ?

something like qobjectlist-based-model to replace my QVariantMap,
https://doc.qt.io/qt-5/qtquick-modelviewsdata-cppmodels.html#qobjectlist-based-model

if it is possible, do i have to do just one setContextProperty() for my CItemModel or do I have to do it for all nested classes ?
thank you very much for your help

[GrecKo]

@arctik There's nothing specific or blocking about nested models in C++ or QML. Just return a model for one of the role of your outer model.