Problemas with mouseMoveEvent - Wont Catch Any Movement

Hey,

I'm having trouble setting up mouseMoveEvent. I setted up a mousePressEvent and it works just fine, but I wont get any response from the
mouseMoveEvent.

I need to catch the mouse position when its moving. Its not implemented yet, but once I grab hold of the mouse movements I will send the positions that are changing to a function to process these movements.

This is the code that I have:

Code:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
#include <QMainWindow>
#include <QGraphicsScene>
#include <QGraphicsLineItem>
#include <QGraphicsSceneMouseEvent>
 
namespace Ui {
    class MainWindow;
}
 
class MainWindow : public QMainWindow
{
    Q_OBJECT
 
public:
    explicit MainWindow(QWidget *parent = 0);
    virtual void mousePressEvent(QMouseEvent *qme1);
    virtual void mouseMoveEvent(QGraphicsSceneMouseEvent *mme2);
    void createLine();
    qreal x1,x2,y1,y2;
    int i;
    QGraphicsScene *scene;
 
 
    ~MainWindow();
 
public slots:
    void criarLinha();
 
 
 
private:
    Ui::MainWindow *ui;
};
 
#endif // MAINWINDOW_H
 
-------//------
 
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QGraphicsScene>
#include <QGraphicsLineItem>
#include <QEvent>
#include <QDropEvent>
#include <QSignalMapper>
#include <QMouseEvent>
#include <QtDebug>
 
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
   ui->setupUi(this);
    MainWindow::setCentralWidget(ui->graphicsView);
    QObject::connect(ui->action_Line,SIGNAL(triggered()),this,SLOT(criarLinha()));
    ui->graphicsView->setMouseTracking(true);
 
 
    i = 0;
    x1 = 0;
    y1 = 0;
    x2 = 0;
    y2 = 0;
 
    scene = new QGraphicsScene;
    ui->graphicsView->setScene(scene);
    scene->installEventFilter(this);
 
 
 
}
 
MainWindow::~MainWindow()
{
    delete ui;
}
 
// Pulbic Functions
void MainWindow::createLine()
{
    QGraphicsLineItem *linha = new QGraphicsLineItem(x1,y1,x2,y2);
    scene->addItem(linha);
}
 
void MainWindow::mousePressEvent(QMouseEvent *qme1)
{
    QMouseEvent *event = static_cast<QMouseEvent *>(qme1);
 
 
 
    if((event->button() == Qt::LeftButton))
        {
            if(i == 0)
            {
                x1 = dynamic_cast<QMouseEvent*>(event)->x();
                y1 = dynamic_cast<QMouseEvent*>(event)->y();
                qDebug() << "x1 Ã© igual a:" << x1;
                qDebug() << "y1 Ã© igual a:" << y1;
                i = 1;
 
 
            }
            else
            {
                x2 = dynamic_cast<QMouseEvent*>(event)->x();
                y2 = dynamic_cast<QMouseEvent*>(event)->y();
                qDebug() << "x2 Ã© igual a:" << x2;
                qDebug() << "y2 Ã© igual a:" << y2;
                i = 0;
            }
 
        }
}
 
void MainWindow::mouseMoveEvent(QGraphicsSceneMouseEvent *mme)
{
 
    qDebug() << "PQP estou mexendo!!";
 
}
 
 
 
//Public Slots
void MainWindow::criarLinha()
{
    createLine();
}

any help will be appreciated.

tnx,

Added after 54 minutes:

I made it work.

I had to create a class derived from QGraphicView and do another implementation of mouseMoveEvent under it. Any1 can explain why this is necessary?

Why couldnt I just have done it in QMainWindow since it is its central ?