qt子线程刷主线程进度条

子线程如下：
mythread.h：

#ifndef MYTHREAD_H
#define MYTHREAD_H
#include <QThread>
class myThread:public QThread
{
    Q_OBJECT
public:
    myThread();
    ~myThread();
    void run() override;
    bool m_bStart;
signals:
    void updateProgress(const int nNum);
};
#endif // MYTHREAD_H

mythread.cpp：

#include "mythread.h"
myThread::myThread():m_bStart(false)
{

}
myThread::~myThread()
{

}
void myThread::run()
{
    int i = 0;
    while(m_bStart)
    {
        i++;
        emit updateProgress(i);
        msleep(100);
        if(i>99)
            i=0;
    }
}

主线程如下：
mainwindow.h：

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include "mythread.h"

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
    myThread m_thread;
    void updateProgress(int nNum);
private slots:
    void on_pushButton_clicked();

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

mainwindow.cpp：

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    connect(&m_thread,&myThread::updateProgress,this,&MainWindow::updateProgress);
}

MainWindow::~MainWindow()
{
    m_thread.m_bStart = false;
    m_thread.wait();
    delete ui;
}

void MainWindow::updateProgress(int nNum)
{
    ui->progressBar->setValue(nNum);
}

void MainWindow::on_pushButton_clicked()
{
    m_thread.m_bStart = true;
    m_thread.start();
}

主界面上有个按钮和一个进度条

运行效果如下：