TreeWidget

[olivier1978]

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:

#ifndef __OSG_GRAPH_INFO_VISITOR_HPP__
#define __OSG_GRAPH_INFO_VISITOR_HPP__
 
#include <osg/NodeVisitor>
#include <osg/Geode>
#include <osg/Drawable>
 
#include <string>
 
class QTreeView;
class q_osg_tree_item;
 
class osg_graph_info_visitor : public osg::NodeVisitor
{
public:
    osg_graph_info_visitor(QTreeView* view);
 
    std::string spaces() { return std::string(_level*2, ' '); }
 
    virtual void apply( osg::Node& node );
    virtual void apply( osg::Geode& geode );
 
protected:
    QTreeView* _view;
    unsigned int _level;
    q_osg_tree_item* _current_parent;
};
 
#endif // __OSG_GRAPH_INFO_VISITOR_HPP__

#ifndef __OSG_GRAPH_INFO_VISITOR_HPP__
#define __OSG_GRAPH_INFO_VISITOR_HPP__

#include <osg/NodeVisitor>
#include <osg/Geode>
#include <osg/Drawable>

#include <string>

class QTreeView;
class q_osg_tree_item;

class osg_graph_info_visitor : public osg::NodeVisitor
{
public:
    osg_graph_info_visitor(QTreeView* view);

    std::string spaces() { return std::string(_level*2, ' '); }

    virtual void apply( osg::Node& node );
    virtual void apply( osg::Geode& geode );

protected:
    QTreeView* _view;
    unsigned int _level;
    q_osg_tree_item* _current_parent;
};

#endif // __OSG_GRAPH_INFO_VISITOR_HPP__

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Its implementation:

#include "osg_graph_info_visitor.hpp"
 
#include <osg/PagedLOD>
#include <osg/Drawable>
 
#include <QAbstractItemModel>
#include <QTreeView>
#include <QModelIndex>
 
#include <iostream>
 
#include "q_osg_tree_item.hpp"
#include "q_osg_tree_model.hpp"
 
using namespace osg;
using namespace std;
 
Q_DECLARE_METATYPE(std::string);
 
osg_graph_info_visitor::osg_graph_info_visitor(QTreeView* view) :
    _view(view),
    _level(0),
    _current_parent(NULL)
{
    _current_parent = ((q_osg_tree_model*)(_view->model()))->root();
    setTraversalMode(osg::NodeVisitor::TRAVERSE_ALL_CHILDREN);
}
 
void osg_graph_info_visitor::apply( Node& node )
{
    cout << spaces() << "[Node - level " << _level << "] " << node.className() << " #parents --> " << node.getNumParents() << endl;
 
    QVector<QVariant> data;
    data.push_back( QVariant::fromValue(string(node.className())) );
 
    _current_parent->insertChildren(_current_parent->childCount(), 1, 1 /*TODO*/);
    for (int column = 0; column < data.size(); ++column)
    {
        cout << "ljifs" << endl;
        _current_parent->child(_current_parent->childCount() - 1)->setData(column, data[column]);
    }
 
    _level++;
    traverse( node );
    _level--;
}
 
void osg_graph_info_visitor::apply( Geode& geode )
{
    cout << spaces() << "[Geode - level " << _level << "] " << geode.className() << endl;
 
    QVector<QVariant> data;
    data.push_back( QVariant::fromValue(string(geode.className())) );
 
    _current_parent->insertChildren(_current_parent->childCount(), 1, 1 /*TODO*/);
    for (int column = 0; column < data.size(); ++column)
    {
        cout << "ljifsqmslksdmlks" << endl;
        _current_parent->child(_current_parent->childCount() - 1)->setData(column, data[column]);
    }
 
    _level++;
    traverse( geode );
    _level--;
}

#include "osg_graph_info_visitor.hpp"

#include <osg/PagedLOD>
#include <osg/Drawable>

#include <QAbstractItemModel>
#include <QTreeView>
#include <QModelIndex>

#include <iostream>

#include "q_osg_tree_item.hpp"
#include "q_osg_tree_model.hpp"

using namespace osg;
using namespace std;

Q_DECLARE_METATYPE(std::string);

osg_graph_info_visitor::osg_graph_info_visitor(QTreeView* view) :
    _view(view),
    _level(0),
    _current_parent(NULL)
{
    _current_parent = ((q_osg_tree_model*)(_view->model()))->root();
    setTraversalMode(osg::NodeVisitor::TRAVERSE_ALL_CHILDREN);
}

void osg_graph_info_visitor::apply( Node& node )
{
    cout << spaces() << "[Node - level " << _level << "] " << node.className() << " #parents --> " << node.getNumParents() << endl;

    QVector<QVariant> data;
    data.push_back( QVariant::fromValue(string(node.className())) );

    _current_parent->insertChildren(_current_parent->childCount(), 1, 1 /*TODO*/);
    for (int column = 0; column < data.size(); ++column)
    {
        cout << "ljifs" << endl;
        _current_parent->child(_current_parent->childCount() - 1)->setData(column, data[column]);
    }

    _level++;
    traverse( node );
    _level--;
}

void osg_graph_info_visitor::apply( Geode& geode )
{
    cout << spaces() << "[Geode - level " << _level << "] " << geode.className() << endl;

    QVector<QVariant> data;
    data.push_back( QVariant::fromValue(string(geode.className())) );

    _current_parent->insertChildren(_current_parent->childCount(), 1, 1 /*TODO*/);
    for (int column = 0; column < data.size(); ++column)
    {
        cout << "ljifsqmslksdmlks" << endl;
        _current_parent->child(_current_parent->childCount() - 1)->setData(column, data[column]);
    }

    _level++;
    traverse( geode );
    _level--;
}

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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:

q_osg_treeview::q_osg_treeview(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::qosgtreeview)
{
    ui->setupUi(this);
 
    QStringList headers;
    headers << "Nodes";
    _model = new q_osg_tree_model(headers, "");
 
    _view = new QTreeView;
    _view->setModel(_model);
 
    ui->verticalLayout->addWidget(_view);
}
 
void q_osg_treeview::toolbutton_input_fileSelected(const QString& file)
{
    QDir current_dir;
    QSettings application_settings;
    const QString DEFAULT_INPUT_DIR_KEY("default_input_dir");
    application_settings.setValue(DEFAULT_INPUT_DIR_KEY, current_dir.absoluteFilePath(file));
 
    ref_ptr<Node> input = osgDB::readNodeFile( file.toStdString() );
 
    osg_graph_info_visitor* v= new osg_graph_info_visitor(_view);
    input->accept(*v);
 
    cout << ((q_osg_tree_model*)_view->model())->root()->childCount() << endl;
}

q_osg_treeview::q_osg_treeview(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::qosgtreeview)
{
    ui->setupUi(this);

    QStringList headers;
    headers << "Nodes";
    _model = new q_osg_tree_model(headers, "");

    _view = new QTreeView;
    _view->setModel(_model);

    ui->verticalLayout->addWidget(_view);
}

void q_osg_treeview::toolbutton_input_fileSelected(const QString& file)
{
    QDir current_dir;
    QSettings application_settings;
    const QString DEFAULT_INPUT_DIR_KEY("default_input_dir");
    application_settings.setValue(DEFAULT_INPUT_DIR_KEY, current_dir.absoluteFilePath(file));

    ref_ptr<Node> input = osgDB::readNodeFile( file.toStdString() );

    osg_graph_info_visitor* v= new osg_graph_info_visitor(_view);
    input->accept(*v);

    cout << ((q_osg_tree_model*)_view->model())->root()->childCount() << endl;
}

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[anda_skoa]

Well, the interesting thing would be the model, after all this is the interface to the data.

Btw, a tree model is the most complicated to implement. Maybe start with a QAbstractListModel as the base class first (just rowCount() and data() to implement), then change to a QAbstractTableModel (additionally requires columnCount()) and only get into a full tree model (by deriving from QAbstractItemModel, requires to also implement index(), parent(), etc) once you've got the two easier ones to work.

Cheers,
_