我把 .ui 文件转换为了 .h 文件，但不知道如何调用，有人会吗，搜索了很久未果。

/********************************************************************************
** Form generated from reading UI file 'mainwindowC20256.ui'
**
** Created by: Qt User Interface Compiler version 5.9.9
**
** WARNING! All changes made in this file will be lost when recompiling UI file!
********************************************************************************/

#ifndef MAINWINDOWC20256_H
#define MAINWINDOWC20256_H

#include <QtCore/QVariant>
#include <QtWidgets/QAction>
#include <QtWidgets/QApplication>
#include <QtWidgets/QButtonGroup>
#include <QtWidgets/QHeaderView>
#include <QtWidgets/QLabel>
#include <QtWidgets/QMainWindow>
#include <QtWidgets/QMenuBar>
#include <QtWidgets/QPushButton>
#include <QtWidgets/QStatusBar>
#include <QtWidgets/QWidget>

QT_BEGIN_NAMESPACE

class Ui_MainWindow
{
public:
    QWidget *centralwidget;
    QLabel *label;
    QPushButton *pushButton;
    QMenuBar *menubar;
    QStatusBar *statusbar;

    void setupUi(QMainWindow *MainWindow)
    {
        if (MainWindow->objectName().isEmpty())
            MainWindow->setObjectName(QStringLiteral("MainWindow"));
        MainWindow->resize(800, 600);
        QFont font;
        font.setPointSize(12);
        MainWindow->setFont(font);
        centralwidget = new QWidget(MainWindow);
        centralwidget->setObjectName(QStringLiteral("centralwidget"));
        label = new QLabel(centralwidget);
        label->setObjectName(QStringLiteral("label"));
        label->setGeometry(QRect(270, 110, 241, 131));
        QFont font1;
        font1.setFamily(QString::fromUtf8("\345\276\256\350\275\257\351\233\205\351\273\221 Light"));
        font1.setPointSize(34);
        label->setFont(font1);
        pushButton = new QPushButton(centralwidget);
        pushButton->setObjectName(QStringLiteral("pushButton"));
        pushButton->setGeometry(QRect(280, 270, 201, 81));
        QFont font2;
        font2.setFamily(QString::fromUtf8("\345\276\256\350\275\257\351\233\205\351\273\221 Light"));
        font2.setPointSize(31);
        pushButton->setFont(font2);
        MainWindow->setCentralWidget(centralwidget);
        menubar = new QMenuBar(MainWindow);
        menubar->setObjectName(QStringLiteral("menubar"));
        menubar->setGeometry(QRect(0, 0, 800, 26));
        MainWindow->setMenuBar(menubar);
        statusbar = new QStatusBar(MainWindow);
        statusbar->setObjectName(QStringLiteral("statusbar"));
        MainWindow->setStatusBar(statusbar);

        retranslateUi(MainWindow);
        QObject::connect(pushButton, SIGNAL(clicked()), MainWindow, SLOT(close()));

        QMetaObject::connectSlotsByName(MainWindow);
    } // setupUi

    void retranslateUi(QMainWindow *MainWindow)
    {
        MainWindow->setWindowTitle(QApplication::translate("MainWindow", "MainWindow", Q_NULLPTR));
        label->setText(QApplication::translate("MainWindow", "hello,world!", Q_NULLPTR));
        pushButton->setText(QApplication::translate("MainWindow", "exit", Q_NULLPTR));
    } // retranslateUi

};

namespace Ui {
    class MainWindow: public Ui_MainWindow {};
} // namespace Ui

QT_END_NAMESPACE

#endif // MAINWINDOWC20256_H

上面是代码