class MyThread : public QThread
{
    QTextEdit* textEdit;
    volatile int val;
  public:
    void set_textEdit(QTextEdit* p){textEdit=p;}
    void set_val(const int v){val=v;}
    void run();
};
class dlgTest: public QDialog, public Ui_dlgTest
{
    Q_OBJECT
    MyThread thread; 
  public:  
    dlgTest(QWidget *parent= 0 );  
  public slots:
    void  on_pbSetThread_clicked();
};
dlgTest::dlgTest(QWidget *parent):QDialog(parent)
{
  setupUi(this);
  thread.set_textEdit(textEdit);
} 
void dlgTest::on_pbSetThread_clicked()
{
  thread.set_val( spinBox->value() );
  thread.start();
}
void MyThread::run()
{
  int x;
  for (int i =  0 ; i <val; ++i) 
  {
    x=i* 2 ;
    textEdit->insertHtml ("test №"+QString::number(x)+" completed"); 
  } 
}