注意点：

转换时，留心转换的16进制是大端结构，还是小端结构。是否需要倒转？

    QString src = "e38B2760";

    int length = src.length();

    QString hex;

    if (length ==8)
    {
        QString x1 = src.mid(6,2);
        QString x2 = src.mid(4,2);
        QString x3 = src.mid(2,2);
        QString x4 = src.mid(0,2);


        hex.append(x1);
        hex.append(x2);
        hex.append(x3);
        hex.append(x4);
    }

    if (length ==7)
    {
        QString x1 = src.mid(5,2);
        QString x2 = src.mid(3,2);
        QString x3 = src.mid(1,2);
        QString x4 = src.mid(0,2);


        hex.append(x1);
        hex.append(x2);
        hex.append(x3);
        hex.append('0');
        hex.append(x4);
    }


    //QString hex1 = "60278Be3";

    bool ok;
    int dec = hex.toInt(&ok, 16);
    qDebug() << dec;
    //1613204451