QT 点击关闭按钮时提示是否退出同时按钮显示为中文

//以Dialog为例
//Dialog.h
#include <QCloseEvent> //加上头文件
class Dialog : public QDialog
{
    Q_OBJECT
public:
    explicit Dialog(QWidget *parent = 0);
    void closeEvent(QCloseEvent *event); //在Dialog.h加上这句
    ...
  //省略其他代码
  ...
};
//Dialog.cpp
#include <QCloseEvent>
#include <QMessageBox>
void Dialog::closeEvent(QCloseEvent *event)
{
    QMessageBox button(QMessageBox::Warning, QString(tr("警告")),QString(tr("警告：正在试图结束程序！")));
    button.setStandardButtons (QMessageBox::Yes|QMessageBox::No);
    button.setButtonText (QMessageBox::Yes,QString("结束"));
    button.setButtonText (QMessageBox::No,QString("返回"));
    if(button.exec() != QMessageBox::Yes)
    {
            event->ignore();
    }
}