求教QNetworkAccessManager下载图片问题 [复制链接]

manager = new QNetworkAccessManager(this);

    connect(manager,SIGNAL(finished(QNetworkReply*)),this,SLOT(replyFinished(QNetworkReply*)));
    QUrl url("http://172.20.18.64/test.png");
    reply = manager->get(QNetworkRequest(url));


void amplyDialog::replyFinished(QNetworkReply *reply)
{
    QTextCodec *codec = QTextCodec::codecForName("utf8");
    //使用utf8编码，这样才可以显示中

    QImageReader imageReader(reply);
    QImage pic = imageReader.read();
    QPixmap img;
    //img.fromImage(pic);
    QByteArray bytes = reply->readAll();
    /*QBuffer buff(&bytes);
    buff.open(QIODevice::ReadWrite);*/
    img.loadFromData(bytes,"png");
    img.save("C:/test.jpg","png");
    ui->label_2->setPixmap(img);
    qDebug ("here");
    reply->deleteLater();
}



为什么我下载下来的图片 无法在Qlabel上显示出来啦 调试 似乎已经全部运行了 求救啊~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

QLabel上不能加图片吧  用QPushButton或QFrame就可以了