QStandardItemModel appendRow doesn't update QML TreeView

SGaist

What did you change in you subclass regarding QStandardItemModel ?

BitteWenden

Nothing apart from custom roles I use in childEntry->setData.

class ProjectTreeModel : public QStandardItemModel
{
    Q_OBJECT
public:
    explicit ProjectTreeModel(QObject *parent = 0);
    virtual ~ProjectTreeModel() = default;

    Q_INVOKABLE QString initializeModel(QString dirLoation);
    enum ProjectTreeModel_Roles
    {
        ProjectTreeModel_Role_Name = Qt::DisplayRole,
        ProjectTreeModel_Role_Type = Qt::WhatsThisRole,
        ProjectTreeModel_Role_Icon = Qt::DecorationRole
    };

    QHash<int, QByteArray> roleNames() const override;

private:
    void addChildEntry( const QString& name, const QString& type, const QString& icon, QStandardItem parent);
    void addRootEntry( const QString& name, const QString& type, const QString& icon);
    QHash<int, QByteArray> m_roleNameMapping;
};

This is my class, so as you can see there is nothing really done with it.

SGaist

How/where are you appending rows outside the constructor ?

BitteWenden

In the addRootEntry (and later in the addChildEntry where it should add a child to a given QStandardItem) in reaction to a button press.

auto rootEntry = new QStandardItem( name );

    rootEntry->setData( icon, ProjectTreeModel_Role_Icon );
    rootEntry->setData( type, ProjectTreeModel_Role_Type );
    rootEntry->setData( name, ProjectTreeModel_Role_Name );

    invisibleRootItem()->appendRow(rootEntry);

This is what it does.

BitteWenden

Do I need to tell my view somehow that the model got updated?

SGaist

I'd emit dataChanged with the new index passing your custom roles.

BitteWenden

I added emit dataChanged(QModelIndex(), QModelIndex(), roles); after my appendRow, which should update the whole view(?), but it still doesn't work.

BitteWenden

This is my whole class right now, in case that helps:

ProjectTreeModel::ProjectTreeModel(QObject *parent) :
    QStandardItemModel(parent)
{

    m_roleNameMapping[ProjectTreeModel_Role_Name] = "name_role";
    m_roleNameMapping[ProjectTreeModel_Role_Type] = "type_role";
    m_roleNameMapping[ProjectTreeModel_Role_Icon] = "icon_role";


}

void ProjectTreeModel::addRootEntry( const QString& name, const QString& type, const QString& icon)
{
    auto rootEntry = new QStandardItem( name );

    rootEntry->setData( icon, ProjectTreeModel_Role_Icon );
    rootEntry->setData( type, ProjectTreeModel_Role_Type );
    rootEntry->setData( name, ProjectTreeModel_Role_Name );

    invisibleRootItem()->appendRow(rootEntry);
    qDebug() << rootEntry;
    qDebug() << this->rowCount();

    QVector<int> vector(0);
    vector.append(ProjectTreeModel_Role_Icon);
    vector.append(ProjectTreeModel_Role_Type);
    vector.append(ProjectTreeModel_Role_Name);

    emit dataChanged(QModelIndex(), QModelIndex(), vector);
}


QHash<int, QByteArray> ProjectTreeModel::roleNames() const
{
    return m_roleNameMapping;
}

SGaist

AFAIK, no. You are passing two invalid indexes. If you want to trigger a refresh, give the top left and bottom right indexes of the part of the model that should get refreshed on the view.

BitteWenden

Okay, tried it with emit dataChanged(invisibleRootItem()->index(), rootEntry->index(), vector); which should work, but it doesn't.

BitteWenden

Or at least I think that should update everything from the root item to the newly created entry.

SGaist

How are you adding that new row outside the constructor ?

BitteWenden

With the appendRow() method (on the invisible root item) as mentioned earlier.

SGaist

I meant, where are you calling appendRow ?

BitteWenden

In a function that is called in response to a button click. (that function calls addRootItem multiple times)

Orkblutt

What about using beginInsertRows() / endInsertRow() ?

BitteWenden

That doesn't seem to work either.

BitteWenden

Does anyone know of some piece of sample code for a dynamic model with Qt Quick and QStandardItemModel where you can add rows and edit items after the construction?

BitteWenden

Oh, Damnit. I had a ProjectTreeViewModel { id:projecttreeviewmodel } in my UI components and used that instead of my treeviewmodel added as a context property.

SGaist

Sneaky one !

Glad you found out :)