求助：这个程序究竟哪里错了

下面这个程序的功能是：
客户端先向服务器发送“1”，然后服务器向客户端发出询问("Are you a boy")，
用户如果选close，就结束通信
选yes，则向服务器发送2，然后在服务器界面上显示"He is a boy"，服务器向客户端发送"Oh, you are a boy"
选no，则向服务器发送3，然后在服务器界面上显示"She is a girl"，服务器向客户端发送"Oh, you are a girl"
最后，客户端弹出一个消息窗口，显示"Oh, you are a boy"或"Oh, you are a girl"，结束。

但不知为什么，最后并没有弹出那个消息窗口，客户端似乎没有收到信息。
这是为什么呢？应该怎么改正？

客户端：

//trycli.h



#ifndef TRYCLI_H_

#define TRYCLI_H_



#include <QtGui/QWidget>

#include <QtNetwork/QTcpSocket>

#include <QtGui/QPushButton>

#include <QtCore/QString>

#include <QtCore/QVector>

#include <QtCore/QTimer>

#include "ui_client.h"



class client : public QWidget

{

	Q_OBJECT

private:

	QPushButton *start;

	QTcpSocket *tcpclient;

	quint16 blockSize;

	QString sendString;

	QString readString;



public:

	client();

	~client();

	void Question(const QString &str);



	public slots:

		void displayError(QAbstractSocket::SocketError socketError);

		void newConnect();

		void clickedStartButton();

		void readMessage();

		void sendMessage();

		

};



#endif





//trycli.cpp



#include "trycli.h"

#include <QtGui/QMessageBox>

#include <QtGui/QHBoxLayout>

#include <QtEvents>



client::client()

{

	setWindowTitle("client");

	resize(100, 100);



	start = new QPushButton("start");

	QHBoxLayout *layout = new QHBoxLayout;

	layout->addWidget(start);

	setLayout(layout);



	tcpclient = new QTcpSocket(this);

	connect(start, SIGNAL(clicked()), this, SLOT(clickedStartButton()));

	connect(tcpclient, SIGNAL(connected()), this, SLOT(sendMessage()));

	connect(tcpclient, SIGNAL(readyRead()), this, SLOT(readMessage()));

	connect(tcpclient, SIGNAL(error(QAbstractSocket::SocketError)),

		this, SLOT(displayError(QAbstractSocket::SocketError)));

}



client::~client()

{



}



void client::newConnect()

{

	blockSize = 0;

	tcpclient->abort();

	tcpclient->connectToHost("127.0.0.1", 8888);

	tcpclient->waitForReadyRead();

}



void client::sendMessage()

{

	QByteArray block;

	QDataStream out(&block, QIODevice::WriteOnly);

	out.setVersion(QDataStream::Qt_4_0);



	out << (quint16)0;

	out << sendString;

	out.device()->seek(0);

	out << (quint16)(block.size() - sizeof(quint16));



	tcpclient->write(block);

}



void client::readMessage()

{

	QDataStream in(tcpclient);

	in.setVersion(QDataStream::Qt_4_0);



	if (blockSize == 0)

	{

		if (tcpclient->bytesAvailable() < (int)sizeof(quint16))

			return;

		in >> blockSize;

	}

	if (tcpclient->bytesAvailable() < blockSize)

		return;



	in >> readString;

	if(readString[0] == 'A')

		Question(readString);

	else

		QMessageBox::about(NULL, "AA", readString);

	tcpclient->disconnectFromHost();

}



void client::displayError(QAbstractSocket::SocketError socketError)

{

	switch (socketError) {

	case QAbstractSocket::RemoteHostClosedError:

		break;

	case QAbstractSocket::HostNotFoundError:

		QMessageBox::information(this, tr("Fortune Client"),

			tr("The host was not found. Please check the "

			"host name and port settings."));

		break;

	case QAbstractSocket::ConnectionRefusedError:

		QMessageBox::information(this, tr("Fortune Client"),

			tr("The connection was refused by the peer. "

			"Make sure the fortune server is running, "

			"and check that the host name and port "

			"settings are correct."));

		break;

	default:

		QMessageBox::information(this, tr("Fortune Client"),

			tr("The following error occurred: %1.")

			.arg(tcpclient->errorString()));

	}

}



void client::clickedStartButton()

{

	sendString = "1";

	newConnect();

}



void client::Question(const QString &str)

{

	QMessageBox::StandardButton rb = QMessageBox::question(NULL, 

		"question", str, 

		QMessageBox::Yes | QMessageBox::No | QMessageBox::Close, 

		QMessageBox::Yes);

	if(QMessageBox::Yes == rb)

	{

		sendString = "2";

		newConnect();

	}

	else if(QMessageBox::No == rb)

	{

		sendString = "3";

		newConnect();

	}

}





//main.cpp



#include "trycli.h"

#include <QtGui/QApplication>



int main(int argc, char *argv[])

{

	QApplication app(argc, argv);

	client w;

	w.show();

	return app.exec();

}