我有这个示例代码：

QDialog *dialog = new QDialog(this);
QPoint dialogPos = dialog->mapToGlobal(dialog->pos());
QPoint thisPos = mapToGlobal(this->pos());
dialog->exec();

但是Dialog并不以他的父母为中心.提前致谢.

更新：

我在MainWindow中从构造函数调用Dialog：

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{

    this->panelInferior = new WidgetTabsInferior;
    this->acciones = new Acciones(this);

    crearAcciones();
    crearBarraMenu();
    crearToolbar();
    crearTabsEditor();
    crearArbolDir();
    crearDockWindows();
    crearStatusBar();

    setWindowIcon(QIcon(":imgs/logo.png"));

    connect(this->pestanasEditor , SIGNAL(currentChanged(int)),this,SLOT(cambioTab(int)));

    this->dialogo = new AcercaDe(this);
    this->dialogo->move(x() + (width() - dialogo->width()) / 2,
                 y() + (height() - dialogo->height()) / 2);
    this->dialogo->show();
    this->dialogo->raise();
    this->dialogo->activateWindow();

}

但我得到的是：

解决方法:

我在github有这个代码

inline void CenterWidgets(QWidget *widget, QWidget *host = 0) {
    if (!host)
        host = widget->parentWidget();

    if (host) {
        auto hostRect = host->geometry();
        widget->move(hostRect.center() - widget->rect().center());
    }
    else {
        QRect screenGeometry = QApplication::desktop()->screenGeometry();
        int x = (screenGeometry.width() - widget->width()) / 2;
        int y = (screenGeometry.height() - widget->height()) / 2;
        widget->move(x, y);
    }
}

希望能帮助到你