问题描述
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使用Qt编写聊天。有问题。我的客户端的QTcpsocket保持连接状态,但是服务器发出newConnection()信号。不需要网络会话。这是为什么?这是一些代码:
ChatClient::ChatClient(QObject *parent)
: QObject(parent) {
tcpsocket = new QTcpsocket(this);
QNetworkConfigurationManager manager;
if (QNetworkConfigurationManager::NetworkSessionrequired
& manager.capabilities()) {
qDebug() << \"Network session required\";
}
connect(tcpsocket,SIGNAL(error(QAbstractSocket::SocketError)),this,SLOT(error(QAbstractSocket::SocketError)));
connect(tcpsocket,SIGNAL(connected()),SLOT(requestForID()));
connect(tcpsocket,SIGNAL(readyRead()),SLOT(receiveMessage()));
tcpsocket->connectToHost(\"192.168.0.100\",PORT);
}
void ChatClient::requestForID() {
qDebug() << \"Connected,requesting for ID\";
QByteArray segment;
QDataStream out(&segment,qiodevice::writeonly);
out.setVersion(QDataStream::Qt_4_7);
out << (quint16)0 << ID;
out.device()->seek(0);
out << (quint16)(segment.size() - sizeof(quint16));
tcpsocket->write(segment);
}
requestForID()从未执行
ChatServer::ChatServer(QObject *parent)
: QObject(parent) {
tcpserver = new QTcpserver(this);
if (!tcpserver->listen(QHostAddress::Any,PORT)) {
qDebug() << \"Unable to start the server\"
<< tcpserver->errorString();
}
qDebug() << \"Server port\" << tcpserver->serverPort();
connect(tcpserver,SIGNAL(newConnection()),SLOT(processConnection()));
}
void ChatServer::processConnection() {
qDebug() << \"Incoming connection\";
QTcpsocket *clientSocket = tcpserver->nextPendingConnection();
/*connect(clientSocket,SLOT(readData()));
readData(clientSocket);
connect(clientSocket,SIGNAL(disconnected()),clientSocket,SLOT(deleteLater()));*/
QByteArray segment;
QDataStream out(&segment,qiodevice::writeonly);
out.setVersion(QDataStream::Qt_4_7);
out << (quint16)0 << (quint16)Message
<< \"Successfully connected\";
out.device()->seek(0);
out << (quint16)(segment.size() - sizeof(quint16));
clientSocket->write(segment);
clientSocket->disconnectFromHost();
}
服务器显示传入连接,并且客户端不发出处于连接状态的连接,也不会接收服务器消息...
有任何想法吗?
解决方法
我遇到了同样的问题,并且找到了原因和解决方案。
connectToHost
可能不会在主窗口的构造函数中直接调用。为什么?
原因是,此时主消息循环尚未运行。内部QAbstractSocketPrivate::fetchConnectionParameters()
不会被调用,并且Qt套接字超时计时器认为永远不会建立连接。
解决方案是将其称为“延迟”,例如
QMetaObject::invokeMethod(this,\"OnDelayedConnect\",Qt::QueuedConnection);
或在connectToHost
之后呼叫waitForConnected()