#include "mainwindow.h"

#include "ui_mainwindow.h"

#include <QtNetwork>

#include <QDebug>

MainWindow::MainWindow(QWidget *parent) :

    QMainWindow(parent),

    ui(new Ui::MainWindow)

{

    ui->setupUi(this);

    tcpServer = new QTcpServer(this);

    //使用了IPv4的本地主机地址，等价于QHostAddress("127.0.0.1")

    if(!tcpServer->listen(QHostAddress::LocalHost, )) {

        qDebug()<<tcpServer->errorString();

        close();

    }

    connect(tcpServer, SIGNAL(newConnection()), this, SLOT(sendMessage()));

}

MainWindow::~MainWindow()

{

    delete ui;

}

void MainWindow::sendMessage()

{

    //用于暂存要发送的数据

    QByteArray block;

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

    //设置数据流的版本，客户端和服务器端使用的版本要相同

    out.setVersion(QDataStream::Qt_4_0);

    out<<(quint16);                            //用两个字节表示数据长度

    out<<tr("hello TCP!!!");

    out.device()->seek();

    out<<(quint16)(block.size() - sizeof(quint16));     //总数据大小减去数据块开头两个字节大小

    //获取已建立的连接的套接字

    QTcpSocket *clientConnection = tcpServer->nextPendingConnection();

    connect(clientConnection, SIGNAL(disconnected()), clientConnection, SLOT(deleteLater()));       //失去连接后删除

    clientConnection->write(block);

    clientConnection->disconnectFromHost();         //等待数据发送完毕后关闭

    //发送数据成功后，显示提示

    ui->label->setText("send message successful!!!");

}

#include "mainwindow.h"

#include "ui_mainwindow.h"

#include <QtNetwork>

#include <QDebug>

MainWindow::MainWindow(QWidget *parent) :

    QMainWindow(parent),

    ui(new Ui::MainWindow)

{

    ui->setupUi(this);

    tcpSocket = new QTcpSocket(this);

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

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

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

}

MainWindow::~MainWindow()

{

    delete ui;

}

void MainWindow::newConnect()

{

    //初始化数据大小信系为0

    blockSize = ;

    //取消已有的连接

    tcpSocket->abort();

    tcpSocket->connectToHost(ui->hostLineEdit->text(), ui->portLineEdit->text().toInt());

}

void MainWindow::readMessage()

{

    QDataStream in(tcpSocket);

    //设置数据流版本，这里要和服务器端相同

    in.setVersion(QDataStream::Qt_4_6);

    //如果是刚开始接收数据

    if(blockSize == ) {

        //判断接收的数据是否大于两个字节，也就是文件的大小信息所占的空间

        //如果是则保存到blockSize变量中，否则直接返回，继续接收数据

        if(tcpSocket->bytesAvailable()<(int)sizeof(quint16)) return;

        in>>blockSize;

    }

    //如果没有得到全部的数据，则返回，继续接收数据

    if(tcpSocket->bytesAvailable() < blockSize) return;

    //将接收到的数据存放到变量中

    in>>message;

    //显示接收到的数据

    qDebug()<<message;

    ui->messageLabel->setText(message);

}

void MainWindow::displayError(QAbstractSocket::SocketError)

{

    qDebug()<<tcpSocket->errorString();

}

void MainWindow::on_connectButton_clicked()

{

    newConnect();

}