Hello!

I've started to learn QT4, and I've got a problem. I've created simple application with QTCreator - one window with two tabs on it (QTabWidget with tab and tab_2), Now I've got 3 files:

mainwindow.h
Qt Code: 
  1. #ifndef MAINWINDOW_H
  2. #define MAINWINDOW_H
  3.  
  4. #include <QMainWindow>
  5.  
  6. namespace Ui {
  7.     class MainWindow;
  8. }
  9.  
  10. class MainWindow : public QMainWindow
  11. {
  12.     Q_OBJECT
  13.  
  14. public:
  15.     explicit MainWindow(QWidget *parent = 0);
  16.     ~MainWindow();
  17.  
  18. private:
  19.     Ui::MainWindow *ui;
  20. };
  21.  
  22. #endif // MAINWINDOW_H
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mainwindow.cpp
Qt Code: 
  1. #include "mainwindow.h"
  2. #include "ui_mainwindow.h"
  3.  
  4. MainWindow::MainWindow(QWidget *parent) :
  5.     QMainWindow(parent),
  6.     ui(new Ui::MainWindow)
  7. {
  8.     ui->setupUi(this);
  9. }
  10.  
  11. MainWindow::~MainWindow()
  12. {
  13.     delete ui;
  14. }
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i main.cpp
Qt Code: 
  1. #include <QtGui/QApplication>
  2. #include "mainwindow.h"
  3.  
  4. int main(int argc, char *argv[])
  5. {
  6.     QApplication a(argc, argv);
  7.     MainWindow w;
  8.     w.show();
  9.  
  10.     return a.exec();
  11. }
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Now I want to draw something with QPainter on tab_2. I've read a lot of tutorails but I didn't found it. What should I write and where? I can only paint on MainWindow with MainWindow::PaintEvent. If it's not a problem can someone write me simple code which will work?

thanks in advance
best regards
Tomasz