[Qt-qml] Can I define a declarative component with a list of lists?

[Stephen Kelly]

Hi,

I have a group of QActions defined in c++ that I want to be able to
arrange and access in qml.

I thought of writing two components like this and am wondering if it
is possible:

  KPIM.ActionTreeFactory {
    id :myTree

    actionTree : [
      "edit",
      [
        "cut",
        "copy",
        "move"
      ]
      "view"
      [
        "month",
        "week",
        "day"
      ]
      "message"
      [
        "sign",
          [
            "Use GPG",
            "Use SMime"
          ]
        "encrypt"
        [
            "Use GPG",
            "Use SMime"
        ]
      ]
    ]
  }

  KPIM.ActionMenuContainer {
    x : 100
    y : 100
    width : 200
    height : 200
    numActions : 2

    model : myTree.model
  }

As you can see, the ActionTreeFactory defines a list of lists. I am
hoping I can implement it something like this:


class ActionTreeFactory {
  Q_PROPERTY(QObject model READ model NOTIFY modelChanged )
  Q_PROPERTY(QVariant actionTree READ actionTree WRITE setActionTree )

public:

  void populateModel(const QVariant &actionTree, const QModelIndex &parent)
  {
    QVariantList contents = actionTree.toList();

    foreach (const QVariant &content, contents)
    {
      if (content.type() == QVariant::String)
      {
        QString actionName = content.toString();
        qDebug() << "GOT ACTION" << actionName;
        m_model->appendAction(parent, actionName);
      }
      if (content.type() == QVariant::List)
      {
        qDebug() << "GOT LIST";
        Q_ASSERT(m_model->hasChildren(parent));
        populateModel(content,
m_model->index(m_model->rowCount(parent) - 1, 0, parent));
      }
    }
  }

  void setActionTree(const QVariant &actionTree)
  {
    m_model = new ActionTreeModel(this);
    populateModel(actionTree, QModelIndex());
  }

  QObject* model() const {
    return qobject_cast<QObject*>(m_model);
  }

private:
  QAbstractItemModel *m_model;

};


That is, I'm hoping I can get the action tree somehow as a list of
lists. In my example I assumed I could get it as a QVariant, but if
it's QScriptValue instead I think that would work too. So is some
implementation like that possible?

Turning the tree of action names into a accessible tree of actions is
a separate problem, but I think it's possible. If the above is not
possible though I'll need to come up with another solution. I can't
find much docs on how to implement Components in c++. Does anyone have
a better idea for a scalable solution to defining groups of actions in
QML?

http://doc.trolltech.com/main-snapshot/qdeclarativecomponent.html

I think maybe this would be useful?

http://doc.trolltech.com/main-snapshot/qdeclarativeproperty.html

All the best,

Steve.