QAbstractListModel insertRows not working properly



  • Greetings All,

    I have a subclass of QAbstractListModel and attached this model subclass with GridView. When I remove rows from my subclass, the GridView gets updated but when I insert rows in the model the GridView does not gets updated. I have implemented the removeR

    I have a very simple subclass of QAbstractListModel and I have attached with it a QML GridView. I have two buttons Add/Remove on the GUI. Pressing Add adds a string to the model and gui updated and pressing remove removes last string from the model and gui updates. My problem is when I add only one row is inserted and when I remove nothing happens on the GUI. Given is the implementation of my model subclass and QML file.

    namesmodel.cpp
    @
    NamesModel::NamesModel(QObject *parent) :
    QAbstractListModel(parent)
    {
    QHash<int, QByteArray> roles;
    roles[Qt::UserRole + 1] = "name";
    setRoleNames(roles);
    }
    int NamesModel::rowCount(const QModelIndex &parent) const
    {
    return this->namesList.count();
    }
    QVariant NamesModel::data(const QModelIndex &index, int role) const
    {
    if (!index.isValid())
    return QVariant();

    switch(role) {
    case (Qt::UserRole + 1):
        return this->namesList.at(index.row());
    default:
        return QVariant();
    }
    return QVariant();
    

    }
    bool NamesModel::insertRow(int row, const QModelIndex &parent)
    {
    if ( parent.isValid() )
    return false;
    qDebug() << "Row = " << row;
    beginInsertRows(parent, row, row);
    this->namesList.insert(row, ("Hello World " + QString("%1").arg(row)));
    endInsertRows();
    return true;
    }
    bool NamesModel::insertRows(int row, int count, const QModelIndex &parent)
    {
    int existing_count = this->namesList.count();
    beginInsertRows(parent, row, count);
    for ( int i = existing_count; i < (existing_count + count); i++ )
    this->namesList.insert(i, QString("Multi Hello World = %1").arg(i));
    endInsertRows();
    return true;
    }
    bool NamesModel::removeRows(int row, int count, const QModelIndex &parent)
    {
    int existing_count = this->namesList.count();
    beginRemoveRows(parent, row, count);
    for ( int i = (existing_count + count); i < existing_count; i-- )
    this->namesList.removeAt(i);
    endRemoveRows();
    return true;
    }

    bool NamesModel::removeRow(int row, const QModelIndex &parent)
    {
    beginRemoveRows(parent, row, row);
    this->namesList.removeAt(row);
    endRemoveRows();
    }

    void NamesModel::addName()
    {
    int index = this->namesList.count();
    //insertRow(index, QModelIndex());
    insertRows(index, 5, QModelIndex());
    emit layoutChanged();
    emit dataChanged(this->index(index), this->index(this->namesList.count()));
    }
    void NamesModel::removeName()
    {
    int index = this->namesList.count();
    //removeRow(index, QModelIndex()/this->index(this->namesList.count())/);
    removeRows(index, 5, QModelIndex());
    emit layoutChanged();
    emit dataChanged(this->index(index), this->index(index + 5));
    }
    @

    main.qml
    @
    Rectangle {
    width: 360
    height: 360
    Text {
    height: 20
    width: 360/2;
    text: "Add Name"
    MouseArea {
    anchors.fill: parent
    onClicked: {
    names.addName();
    console.log("Add Name");
    }
    }
    }
    Text {
    height: 20;
    width: 360/2;
    x: 360/2
    text: "Remove Name";
    MouseArea {
    anchors.fill: parent
    onClicked: {
    names.removeName();
    console.log("Remove Name");
    }
    }
    }

    Component {
        id: gridDelegate
    
        Text {
            width: 19;      // These are the dimensions of icon image.
            height: 16
            font.pixelSize: 12
            text: name;
        }
    }
    GridView {
        y: 21
        boundsBehavior: Flickable.StopAtBounds
    
        focus: true
        model: names;
        delegate: gridDelegate
    }
    

    }
    @

    I am calling beginInsertRows / endInsertRows and beginRemoveRows / endRemoveRows but it does not seems to work. As suggested on other similar threads I have also called layoutChanged / dataChanged after begin / end InserRows but no effect.

    Actually I have almost the same problem with my actual project. I have created this application to test whats wrong with this beginInsertRows etc.

    Any help is appreciated.

    Regards Farrukh Arshad.



  • Did you try the model tester on your model? For custom models, that's always your first benchmark to flush out the problems that are in there almost by default :)



  • Thanks Andre. Can you please suggest how can I use model tester ?



  • Sure. Get it from Gitorious, and compile in the header and source. Then, instantiate the tester on your model somewhere in the code. It will print out the found issues on the debug stream.

    See "here":/wiki/Model_Test on the Wiki.


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