QThreadPool::waitForDone()可阻塞线程，采用std::function方式将其置于其它线程执行，避免阻塞线程同时可设置等待框(其它线程)生存期，单纯不阻塞线程可以直接不使用waitForDone。

一.调用

DlgProcess wait(QString("检查中"));
wait.WaitFor([&]()//std::function<void()>& task //&表示引用传递捕捉所有父作用域变量
{
     m_pThreadPool->waitForDone();//猜测只有在此函数作用域内wait导致m_pProgress有效
});

二.DlgProcess

DlgProcess::DlgProcess(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::DlgProcess)
{
    ui->setupUi(this);

    m_timer=new QTimer(this);    
    connect(m_timer, SIGNAL(timeout()), this, SLOT(UpdateMsg()));//每隔1秒刷新
    m_nDotjs=0;
    m_nStep=0;
}

DlgProcess::~DlgProcess()
{
    delete ui;
}

void DlgProcess::WaitFor(const std::function<void()>& task)
{
    int w = 200;
    int h = 100;

    //设置显示位置
    this->setFixedSize(w,h);
    QDesktopWidget* deskWidget = QApplication::desktop();
    QRect deskRect = deskWidget->availableGeometry();//QDesktopWidget
    double x = (deskRect.width() -w)/2;   //设置对话框居中于桌面
    double y = (deskRect.height()-h)/2;
    this->move(x,y);

    this->setWindowModality(Qt::ApplicationModal);
    m_timer->start(1000);//每隔1秒刷新

    this->m_task = task;//std::function<void()>
    //this->exec();//触发showEvent
    if (m_task != nullptr)
    {
        m_thread = new ThreadTask(this,this->m_task);//设置多线程,任务结束时关闭
        m_thread->start();
    }
}

void DlgProcess::setStep(int nStep)
{
    ui->progressBar->setValue(nStep);
    //update();//会调用
}

void DlgProcess::SetMsg(QString sMsg)//修改文本
{
    m_sMsg=sMsg;
    //ui->label->setText(m_sMsg);
}

void DlgProcess::UpdateMsg()
{
    //刷新下面文字
    QString sMsg=m_sMsg;
    for(int i=0;i<m_nDotjs;i++)
    {
        sMsg+=".";
    }
    ++m_nDotjs;
    if(m_nDotjs>3) m_nDotjs=0;
    ui->label->setText(sMsg);

    update();
}

void DlgProcess::showEvent(QShowEvent *event)//初次显示时触发
{
    if (m_task != nullptr)
    {
        m_thread = new ThreadTask(this,this->m_task);//设置多线程,任务结束时关闭
        m_thread->start();
    }
}

三.waitForDone移至QThread运行

ThreadFun::ThreadFun(const std::function<void()>& task)
{
    this->m_task = task;
}
void ThreadFun::run()
{
    if (this->m_task != nullptr)
        this->m_task();//猜测将外部函数移至线程内执行，此处可避免主界面阻塞

    emit taskFinish();
}