奇怪的问题：为什么过4—5分钟后就不进入这个handleUnsupportedContent槽呢

  我在程序中重载了QWebPage这个类，这个类中要实现下载东西到本地。下载在handleUnsupportedContent实现handleUnsupportedContent是unsupportedContent(QNetworkReply *)的槽函数。刚开始4分钟之内能够进入到这个函数当中
但之后就不能进入。这是太奇怪了，不知道为什么。部分代码如下：
setForwardUnsupportedContent (true);
   connect(this, SIGNAL(unsupportedContent(QNetworkReply *)),this, SLOT(handleUnsupportedContent(QNetworkReply *)),Qt::DirectConnection);
void aosMywebPage::handleUnsupportedContent(QNetworkReply *reply)
{

if (reply->error() == QNetworkReply::NoError)
    {
    manager=this->networkAccessManager();
   m_reply=manager->post(request,"save=doc");
             m_reply->setParent(this);
   progressBar->setMinimumSize(500,20);
   progressBar->show();
   connect(m_reply, SIGNAL(readyRead()), this, SLOT(downloadReadyRead()));
   connect(m_reply, SIGNAL(error(QNetworkReply::NetworkError)),
              this, SLOT(error(QNetworkReply::NetworkError)));
   connect(m_reply, SIGNAL(downloadProgress(qint64, qint64)),
              this, SLOT(downloadProgress(qint64, qint64)));
   connect(m_reply, SIGNAL(finished()),
              this, SLOT(finished()));
   return;
    }
}

补充：移动开发 ,  Qt