Hi all,

I am trying to learn MVC within the Qt framework. So, to test, I am developping a small toy application. The idea is to display an OpenSceneGraph scene graph using a QTreeView. Thus, I have a good starting point using the "Editable Tree Model Example". However, after doing a few changes, it appears that my QTreeView is empty. I do not understand why, but I am nearly sure that I am missing the way to insert the root item in the model. Could you please help me?

Basically the item and model are copy / paste of the example. I juste removed the setupModel method from the model and so, do not call it anymore from the constructor.

Regards,

The visitor for all the nodes contained in the scene graph:
Qt Code: 
  1. #ifndef __OSG_GRAPH_INFO_VISITOR_HPP__
  2. #define __OSG_GRAPH_INFO_VISITOR_HPP__
  3.  
  4. #include <osg/NodeVisitor>
  5. #include <osg/Geode>
  6. #include <osg/Drawable>
  7.  
  8. #include <string>
  9.  
  10. class QTreeView;
  11. class q_osg_tree_item;
  12.  
  13. class osg_graph_info_visitor : public osg::NodeVisitor
  14. {
  15. public:
  16.     osg_graph_info_visitor(QTreeView* view);
  17.  
  18.     std::string spaces() { return std::string(_level*2, ' '); }
  19.  
  20.     virtual void apply( osg::Node& node );
  21.     virtual void apply( osg::Geode& geode );
  22.  
  23. protected:
  24.     QTreeView* _view;
  25.     unsigned int _level;
  26.     q_osg_tree_item* _current_parent;
  27. };
  28.  
  29. #endif // __OSG_GRAPH_INFO_VISITOR_HPP__
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Its implementation:
Qt Code: 
  1. #include "osg_graph_info_visitor.hpp"
  2.  
  3. #include <osg/PagedLOD>
  4. #include <osg/Drawable>
  5.  
  6. #include <QAbstractItemModel>
  7. #include <QTreeView>
  8. #include <QModelIndex>
  9.  
  10. #include <iostream>
  11.  
  12. #include "q_osg_tree_item.hpp"
  13. #include "q_osg_tree_model.hpp"
  14.  
  15. using namespace osg;
  16. using namespace std;
  17.  
  18. Q_DECLARE_METATYPE(std::string);
  19.  
  20. osg_graph_info_visitor::osg_graph_info_visitor(QTreeView* view) :
  21.     _view(view),
  22.     _level(0),
  23.     _current_parent(NULL)
  24. {
  25.     _current_parent = ((q_osg_tree_model*)(_view->model()))->root();
  26.     setTraversalMode(osg::NodeVisitor::TRAVERSE_ALL_CHILDREN);
  27. }
  28.  
  29. void osg_graph_info_visitor::apply( Node& node )
  30. {
  31.     cout << spaces() << "[Node - level " << _level << "] " << node.className() << " #parents --> " << node.getNumParents() << endl;
  32.  
  33.     QVector<QVariant> data;
  34.     data.push_back( QVariant::fromValue(string(node.className())) );
  35.  
  36.     _current_parent->insertChildren(_current_parent->childCount(), 1, 1 /*TODO*/);
  37.     for (int column = 0; column < data.size(); ++column)
  38.     {
  39.         cout << "ljifs" << endl;
  40.         _current_parent->child(_current_parent->childCount() - 1)->setData(column, data[column]);
  41.     }
  42.  
  43.     _level++;
  44.     traverse( node );
  45.     _level--;
  46. }
  47.  
  48. void osg_graph_info_visitor::apply( Geode& geode )
  49. {
  50.     cout << spaces() << "[Geode - level " << _level << "] " << geode.className() << endl;
  51.  
  52.     QVector<QVariant> data;
  53.     data.push_back( QVariant::fromValue(string(geode.className())) );
  54.  
  55.     _current_parent->insertChildren(_current_parent->childCount(), 1, 1 /*TODO*/);
  56.     for (int column = 0; column < data.size(); ++column)
  57.     {
  58.         cout << "ljifsqmslksdmlks" << endl;
  59.         _current_parent->child(_current_parent->childCount() - 1)->setData(column, data[column]);
  60.     }
  61.  
  62.     _level++;
  63.     traverse( geode );
  64.     _level--;
  65. }
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And this is from my GUI that I create the model and attache it to the view, and then call the visitor:
Qt Code: 
  1. q_osg_treeview::q_osg_treeview(QWidget *parent) :
  2.     QWidget(parent),
  3.     ui(new Ui::qosgtreeview)
  4. {
  5.     ui->setupUi(this);
  6.  
  7.     QStringList headers;
  8.     headers << "Nodes";
  9.     _model = new q_osg_tree_model(headers, "");
  10.  
  11.     _view = new QTreeView;
  12.     _view->setModel(_model);
  13.  
  14.     ui->verticalLayout->addWidget(_view);
  15. }
  16.  
  17. void q_osg_treeview::toolbutton_input_fileSelected(const QString& file)
  18. {
  19.     QDir current_dir;
  20.     QSettings application_settings;
  21.     const QString DEFAULT_INPUT_DIR_KEY("default_input_dir");
  22.     application_settings.setValue(DEFAULT_INPUT_DIR_KEY, current_dir.absoluteFilePath(file));
  23.  
  24.     ref_ptr<Node> input = osgDB::readNodeFile( file.toStdString() );
  25.  
  26.     osg_graph_info_visitor* v= new osg_graph_info_visitor(_view);
  27.     input->accept(*v);
  28.  
  29.     cout << ((q_osg_tree_model*)_view->model())->root()->childCount() << endl;
  30. }
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