gistfile1.txt

// inside my open_project.cpp file (it is a QDialog window)

open_project::open_project(QWidget *parent) :
    QDialog(parent),
    ui_open_project(new Ui::open_project)
{
    ui_open_project->setupUi(this);
    locations_name = new QStandardItemModel;
    user->initdb();
    locations_refresh();
    model = new QSqlQueryModel();
    model->setQuery("SELECT id, name, comment, refproject, datecreate "
                    "FROM \"Projects\" "
                    "WHERE dateclose IS NULL "
                    "ORDER BY datecreate ;");
    ui_open_project->projects_list->setModel(model);
    ui_open_project->projects_list->setModelColumn(1);
    ui_open_project->projects_list->show();
    ui_open_project->checkBox_location->setChecked(false);
    ui_open_project->treeView_locations->setEnabled(false);
    ui_open_project->pushButton_location->setEnabled(false);
    ui_open_project->checkBox_structure->setChecked(false);
    ui_open_project->treeView_structures->setEnabled(false);
    ui_open_project->pushButton_structure->setEnabled(false);
    ui_open_project->treeView_locations->setModel(locations_name);
    ui_open_project->treeView_locations->setHeaderHidden(true);
}

open_project::~open_project()
{
    delete ui_open_project;
}



void open_project::on_projects_list_clicked(const QModelIndex &index)
{
    QString sformat = QString("dd/MM/yyyy %1 hh:mm:ss").arg(tr("à"));
    name        = model->record(index.row()).value("name").toString();
    comment     = model->record(index.row()).value("comment").toString();
    ref_project = model->record(index.row()).value("refproject").toString();
    date_create = model->record(index.row()).value("datecreate").toString();
    id          = model->record(index.row()).value("id").toInt();
    ui_open_project->label_name->setText(name);
    ui_open_project->comment->setText(comment);
    ui_open_project->ref_client->setText(ref_project);
    ui_open_project->date_create->setText(QString("%1")
                                          .arg(QDateTime::fromString(date_create,
                                               QString("yyyy-MM-dd'T'hh:mm:ss"))
                                               .toString(sformat)));
    if (id != 0)
        locations_refresh();
    ui_open_project->treeView_locations->setColumnHidden(1,true);
}

// this is inside my open_location.cpp file... an other one QDialog window (this one is in construction, but you can open it and click the new location button):

open_Location::open_Location(QWidget *parent) :
    QDialog(parent),
    ui_open_Location(new Ui::open_Location)
{
    ui_open_Location->setupUi(this);
}

open_Location::~open_Location()
{
    delete ui_open_Location;
}

void open_Location::on_add_to_project_clicked()
{

}

void open_Location::on_create_new_location_clicked()
{
    new_location *nl = new new_location(this);
    nl->open();
    QObject::connect(nl, &QDialog::finished, [nl, this](int result){
        if (result)
            int a = result;
        nl->deleteLater();
    });
}




//  this is inside my new_location.cpp file... an other one QDialog window:
new_location::new_location(QWidget *parent) :
    QDialog(parent),
    ui_new_location(new Ui::new_location)
{
    ui_new_location->setupUi(this);
    locations_name = new QStandardItemModel;
    //user->initdb();


    database =  QSqlDatabase::addDatabase("QPSQL");
    database.setDatabaseName("recorder");
    database.setHostName("localhost");
    if(!database.open(QString("admin"), QString("overover")))
    {
        QString err = database.lastError().text();
        errorBox = new QMessageBox();
        errorBox->setInformativeText(QString("erreure lors de l'execution de recherche\ndans la base de donnée:\n%1")
                                 .arg(err));
        errorBox->exec();
        //qDebug() << QString("La base de donnée ne s'est pas connectée correctement:\n%1")
        //                    .arg(err);
    }


    locations_refresh();
    ui_new_location->treeView_parent->setEnabled(false);
    ui_new_location->treeView_parent->setModel(locations_name);
    ui_new_location->treeView_parent->setHeaderHidden(true);
    ui_new_location->treeView_parent->setColumnHidden(1,true);
}

new_location::~new_location()
{
    delete ui_new_location;
}

void new_location::find_Childs(int child_id,  QStandardItem *ref) {
    QHash<int, QString> child_hash = store_DB_locations[child_id];
    foreach(int childId, child_hash.keys()) {
        QStandardItem *child_next_a = new QStandardItem(child_hash[childId]);  // première colonne => nom du lieu
        QStandardItem *child_next_b = new QStandardItem(QString("%1").arg(childId));  // seconde colonne => id
        QList<QStandardItem *> child_next_list;
        child_next_list << child_next_a << child_next_b;
        ref->appendRow(child_next_list);
        find_Childs(childId, child_next_a); }
}

void new_location::locations_refresh() {
    QSqlQuery query;
    query.prepare("SELECT name, id, id_parent FROM \"Locations\""
                  "ORDER by (id_parent, name) ASC;");
    //user->execDB(query);
    query.exec();
    while(query.next())
        store_DB_locations[query.value(2).toInt()].
                insert(query.value(1).toInt(),
                       query.value(0).toString());
    QStandardItem *rootNode = locations_name->invisibleRootItem();
    find_Childs(0, rootNode);
}

QString new_location::name() const
{
    return ui_new_location->lineEdit_name->text() ;
}

QString new_location::comment() const
{
    return ui_new_location->textEdit_comment->toPlainText();
}

void new_location::on_pushButton_REC_clicked()
{
    QSqlQuery query; //(user->currentDB());
    query.prepare("INSERT INTO \"Locations\" "
                  "(name, comment, id_parent) "
                  "VALUES (:name, :comment, :parent);");
    query.bindValue(":name", name());
    query.bindValue(":comment", comment());
    query.bindValue(":parent", id_parent);
    //user->execDB(query);
    query.exec();
    accept();
}

void new_location::on_checkBox_parent_stateChanged(int arg1) {
    if(ui_new_location->checkBox_parent->isChecked())
        ui_new_location->treeView_parent->setEnabled(true);
    else
        ui_new_location->treeView_parent->setEnabled(false);
}

void new_location::on_treeView_parent_clicked(const QModelIndex &index)
{
    int row = index.row();
    QModelIndex the_parent = index.parent();
    name_location = locations_name->data(locations_name->index(row, 0, the_parent), Qt::EditRole).toString();
    id_parent = locations_name->data(locations_name->index(row, 1, the_parent), Qt::EditRole).toInt();
}