Окно ожидания завершения операции, пустой QDialog

QT       += core gui
 
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
 
TARGET = progressTest
TEMPLATE = app
 
 
SOURCES += main.cpp\
        mainwindow.cpp
 
HEADERS  += mainwindow.h
 
FORMS    +=

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
#include <QMainWindow>
 
class QDialog;
class QPushButton;
class QProgressBar;
class QProgressDialog;
 
 
class MainWindow : public QMainWindow
{
    Q_OBJECT
 
public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
 
private:
 
    QDialog *waitingDialog;
 
    QPushButton *button1;
    QPushButton *button2;
 
    QProgressBar *progressBar;
 
    QProgressDialog *progressDialog;
 
    void someLongFunction();
 
private slots:
    void startOperation1();
    void startOperation2();
 
};
 
#endif // MAINWINDOW_H

#include "mainwindow.h"
 
#include <QtWidgets>
#include <QProcess>
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent)
{    
    button1 = new QPushButton(this);
    button1->setText("Start operation - QDialog");
    button2 = new QPushButton(this);
    button2->setText("Start operation - QProgressDialog");
 
    waitingDialog = new QDialog;
    progressBar = new QProgressBar(waitingDialog);
    progressBar->setRange(0, 0);
    progressBar->setFormat("operation");
    QVBoxLayout *waitingDialog_layout = new QVBoxLayout;
    waitingDialog_layout->addWidget(progressBar);
    waitingDialog->setLayout(waitingDialog_layout);
    waitingDialog->resize(200, 30);
 
    progressDialog = new QProgressDialog;
    progressDialog->setRange(0, 0);
    progressDialog->setWindowTitle("Operation");
    progressDialog->setCancelButton(0);
    progressDialog->setLabelText("operation");
    progressDialog->resize(200, 30);
 
    QVBoxLayout *mainLayout = new QVBoxLayout;
    mainLayout->addWidget(button1);
    mainLayout->addWidget(button2);
 
    QWidget *mainWidget = new QWidget(this);
    mainWidget->setLayout(mainLayout);
 
    this->setCentralWidget(mainWidget);
 
    QObject::connect(button1,  SIGNAL(clicked()), this, SLOT(startOperation1()));
    QObject::connect(button2,  SIGNAL(clicked()), this, SLOT(startOperation2()));
}
 
MainWindow::~MainWindow()
{
 
}
 
void MainWindow::startOperation1()
{
    waitingDialog->show();
 
    someLongFunction();
 
    waitingDialog->close();
}
 
void MainWindow::startOperation2()
{
    progressDialog->show();
 
    someLongFunction();
 
    progressDialog->close();
}
 
void MainWindow::someLongFunction()
{
    QProcess *someProcess = new QProcess(this);
    QString program("ping.exe");
    QStringList args;
    args << "127.0.0.1";
    someProcess->execute(program, args);
}

#include "mainwindow.h"
#include <QApplication>
 
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
 
    return a.exec();
}