Qt 对话框显示控制按钮

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

Qt::WindowFlags flags=Qt::Dialog;

flags |=Qt::WindowMinimizeButtonHint;
flags |=Qt::WindowMaximizeButtonHint;
flags |=Qt::WindowCloseButtonHint;
setWindowFlags(flags);

}