So, I created a Qt UI in a ROS node and after some fights with CMakeLists I managed to compile it with catkin.

Now the problem that I have is that I don't know exactly where to put my ROS parameters in the mainwindow.cpp. I have it in a way where I can send messages when I click on the button "Send". However, it only works once because after that the app crashes (I assume the system gets trapped in the while(ros::ok())...)

This is my mainwindow.cpp code (except some callbacks related to some buttons):

#include "ros/ros.h"
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtGui/QPushButton>
#include "globals.h"
#include <QString>
#include <string>
#include <sstream>
#include "QMessageBox"
#include "QTimer"
#include "QTime"
#include "qtgui/GUIDados.h"

using namespace std;
using namespace ros;

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{

    ui->setupUi(this);
    ui->spinBox1->hide();
    ui->spinBox2->hide();
    ui->spinBox3->hide();
    ui->spinBox4->hide();
    ui->spinBox5->hide();
    ui->spinBox6->hide();
    ui->spinBox7->hide();
    ui->spinBox8->hide();
    ui->spinBox9->hide();
    ui->spinBox10->hide();
    ui->spinBox11->hide();
    ui->spinBox12->hide();
    ui->spinBox13->hide();
    ui->spinBox14->hide();
    ui->spinBox15->hide();
    ui->spinBox16->hide();
    ui->spinBoxall->hide();
    numberOfMotors =0;

    int argc = 0;
    char **argv;
    ros::init(argc, argv, "qtgui");
    cout << "init" << endl;

 /*   TIMER */
   QTimer *timer = new  QTimer(this);
    connect(timer, SIGNAL(timeout()), this, SLOT(showTime()));
    timer->start(1000);
    showTime();
}

void MainWindow::showTime()
{
    QTime time = QTime::currentTime();
    QString text = time.toString("hh:mm");
    if ((time.second() % 2) == 0)
        text[2] = ' ';
    cout << "text" << endl;
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_closeButton_clicked()
{
    close();
}

void MainWindow::on_sendButton_clicked()
{
    QMessageBox::information(this,tr("Titulo"),tr("escolheu: %1").arg( intensidade[0])); //dutycycle do motor1
      ros::NodeHandle n;
    cout << "nodehandle" << endl;
    ros::Publisher QtPublisher = n.advertise<qtgui::GUIDados>("guichattergui",1000);
    ros::Rate loop_rate(10); //10hz
    while(ros::ok())
   {
    qtgui::GUIDados msg;

    msg.numeroMotores = numberOfMotors;
    msg.intensidade.resize(16);
    msg.local.resize(16);
    for(int i=0;i<16;i++)
    {
        msg.intensidade[i] = intensidade[i];
        msg.local[i] = local[i];
    }
    QtPublisher.publish(msg);
    ros::spinOnce();

    loop_rate.sleep();
   }
}

What I have so far is that, when I click on send it sends a ros message. I tried to initialize ros in the *MainWindow::MainWindow(QWidget parent) however it didnt exactly work...

As you probably can guess, I'm very new to this Qt interface thing (and also ROS to be fair), so any help would be useful.
Where should I put my ros parameters so that this works fine?

Here's my other parts of the code:
main.cpp:

#include "mainwindow.h"
#include <QtGui/QApplication>
#include "globals.h"
#include "qtgui/GUIDados.h"

using namespace std;

int main(int argc, char *argv[])
{
    std::cout<<"I am Alive!"<<std::endl;

    QApplication a(argc, argv); //creates a QApplication object

    MainWindow w; //creates the main window object
    w.show();

    return a.exec(); //enter its event loop
}

mainwindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT //declares our class as a QObject

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

private slots:
    void showTime();

    void on_closeButton_clicked();

private:
    Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H

Thank you in advance!