Qt学习之路_6(Qt局域网聊天软件)

　　在上2次文章Qt学习之路_5(Qt TCP的初步使用) Qt学习之路_4(Qt UDP的初步使用) 中已经初步介绍了群聊功能和文件传输功能，这一节中主要在这个基础上加入一个私聊功能。

　　参考文献依旧是：《Qt及Qt Quick开发实战精解》一书中的第5个例子以及http://www.yafeilinux.com/ 网站上的源码。另外这次的私聊功能也是参考网友http://www.qtcn.org/bbs/read-htm-tid-32609.html的，他的程序有些bug，其中最严重的bug是当私聊第二次聊天的时候对方会接收不到信息。这次主要是将这个bug和其它一些小bug修补了，但是仍然有一个漏洞就是：当第二次私聊时，后面那个的发送方收到信息的时候有可能会多一个窗口弹出来。目前还找不到其原因。猜想是：在第一次聊天接收时关闭聊天窗口后，其内存没有释放。但是当窗口关闭时我们觉得其内存释放应该在Qt内部自己实现。

下面来讲一下私聊发送端和接收端具体实现过程。

发送端流程图如下：

　　接收端的流程图如下：

　　下面来介绍下2者实现的具体过程：

　　A方(主动开始首次发送的一方)：

在主窗口右侧双击自己想与之聊天的B方，此时A方实际上完成的工作有：用B方的主机名和ip地址新建了私聊的类privatechat，在新建该类的过程中，已经设置了显示顶端为：与***聊天中，对方IP：***，且绑定了本地ip和私聊的专用端口，同时设置了信号与槽的联系，即该端口如果有数据输入，则触发槽函数processPendingDatagrams().该函数是char.cpp中的。
当上面的新建私聊类完成后，用通讯对方ip地址和其群聊专用的端口（但用的是主udp群聊的socket进行的）将以下内容分别发送出去：消息类型(Xchat)，用户名，主机名，本地ip地址。完成后，在屏幕中显示私聊窗口。
在私聊窗口中输入需要聊天的内容，单击发送键。该过程玩成的内容有：分别将消息类型(Message)+用户名+本地名+本地IP+消息内容本身通过私聊专用端口发送出去。在私聊窗口中显示主机名+聊天时间，换行后显示消息内容本身。

　　B方(第一次信息是他人发送过来的)：

当A在2步骤中用群聊的方法发送其消息类型(Xchat)，其用户名，其主机名，其ip地址后，由于程序运行时已经初始化了widget.cpp中的构造函数，所以每个程序都绑定了本地地址+群聊专用的端口，一旦有数据传入，就触发widget.cpp中的槽函数processPendingDatagrams().
在processPendingDatagrams()函数中，判断消息类型为Xchat后，接收缓存区内接收对方用户名，对方主机名和对方ip地址。并用接收到的主机名和ip地址新建一个私聊类。新建该私聊的过程与A中的步骤1一样。完后在程序中显示私聊窗口。
当对方A按完发送按钮后，通过私聊专用端口绑定槽函数来触发chart.cpp中的processPendingDatagrams()函数，该函数中先读取消息类型(Message)，然后依次读取用户名，主机名，ip地址，消息内容本身，并将对方信息和消息内容显示在聊天窗口中。

　　实验结果如下：

　　群聊界面：

　　私聊界面：

　　文件传输过程截图：

　　实验总结（下面几点只是暂时的理解）：

使用类时，如果直接用构造函数定义该类的对象，则定义该类的函数接收时，该对象的生命也就结束了，所以如果要在其他函数中定义一个类的对象时并长久使用，可以使用new定义一个对象的初始指针。这样就在内存中永存了。
如果某个窗口类需要显示时直接调用其指针->show()或者其对象-.show(),这个函数只是将内存中该类的对象显示出来而已（因为与界面有关），并不是重新建一个类对象。其表示该类的界面等可以显示，所以一旦show过即使改变了界面的内容，后面也无需一直调用show函数，界面会自动显示的。
当关闭某个窗口时，只是将其隐藏，并没有释放其内存。

程序源码（附录有工程code下载链接）：

　widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QtNetwork>
#include <QtGui>
#include "tcpclient.h"
#include "tcpserver.h"
#include "chat.h"
using namespace std::tr1;
namespace Ui {
    class Widget;
}

//enum MessageType
//{
//    Message,
//    NewParticipant,
//    ParticipantLeft,
//    FileName,
//    Refuse,
//    xchat
//};
//枚举变量标志信息的类型，分别为消息，新用户加入，和用户退出
class Widget : public QWidget
{
    Q_OBJECT

public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();
    QString getUserName();
    QString getMessage();
    chat* privatechat;
    chat* privatechat1;

protected:
    void changeEvent(QEvent *e);
    void sendMessage(MessageType type,QString serverAddress="");
    void newParticipant(QString userName,QString localHostName,QString ipAddress);
    void participantLeft(QString userName,QString localHostName,QString time);
    void closeEvent(QCloseEvent *);
    void hasPendingFile(QString userName,QString serverAddress,
                        QString clientAddress,QString fileName);

     bool eventFilter(QObject *target, QEvent *event);//事件过滤器
private:
    Ui::Widget *ui;
    QUdpSocket *udpSocket;
    qint32 port;
    qint32 bb;
    QString fileName;
    TcpServer *server;
    //chat *privatechat;

    QString getIP();

    QColor color;//颜色

    bool saveFile(const QString& fileName);//保存聊天记录
    void showxchat(QString name, QString ip);

private slots:
    void on_tableWidget_doubleClicked(QModelIndex index);
    void on_textUnderline_clicked(bool checked);
    void on_clear_clicked();
    void on_save_clicked();
    void on_textcolor_clicked();
    void on_textitalic_clicked(bool checked);
    void on_textbold_clicked(bool checked);
    void on_fontComboBox_currentFontChanged(QFont f);
    void on_fontsizecomboBox_currentIndexChanged(QString );
    void on_close_clicked();
    void on_sendfile_clicked();
    void on_send_clicked();
    void processPendingDatagrams();
    void sentFileName(QString);
    void currentFormatChanged(const QTextCharFormat &format);

signals:


};

#endif // WIDGET_H

widget.cpp:

#include "widget.h"
#include "ui_widget.h"
using namespace std::tr1;
Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);   
    this->resize(850,550);
    ui->textEdit->setFocusPolicy(Qt::StrongFocus);
    ui->textBrowser->setFocusPolicy(Qt::NoFocus);

    ui->textEdit->setFocus();
    ui->textEdit->installEventFilter(this);//设置完后自动调用其eventFilter函数
    privatechat = NULL;
    privatechat1 = NULL;

    udpSocket = new QUdpSocket(this);
    port = 45454;
    bb = 0;
    udpSocket->bind(port,QUdpSocket::ShareAddress | QUdpSocket::ReuseAddressHint);
    connect(udpSocket,SIGNAL(readyRead()),this,SLOT(processPendingDatagrams()));
    sendMessage(NewParticipant);

    server = new TcpServer(this);
    connect(server,SIGNAL(sendFileName(QString)),this,SLOT(sentFileName(QString)));
    connect(ui->textEdit,SIGNAL(currentCharFormatChanged(QTextCharFormat)),this,SLOT(currentFormatChanged(const QTextCharFormat)));

}

void Widget::currentFormatChanged(const QTextCharFormat &format)
{//当编辑器的字体格式改变时，我们让部件状态也随之改变
    ui->fontComboBox->setCurrentFont(format.font());

    if(format.fontPointSize()<9)  //如果字体大小出错，因为我们最小的字体为9
    {
        ui->fontsizecomboBox->setCurrentIndex(3); //即显示12
    }
    else
    {
        ui->fontsizecomboBox->setCurrentIndex(ui->fontsizecomboBox->findText(QString::number(format.fontPointSize())));

    }

    ui->textbold->setChecked(format.font().bold());
    ui->textitalic->setChecked(format.font().italic());
    ui->textUnderline->setChecked(format.font().underline());
    color = format.foreground().color();
}

void Widget::processPendingDatagrams()   //接收数据UDP
{
    while(udpSocket->hasPendingDatagrams())
    {
        QByteArray datagram;
        datagram.resize(udpSocket->pendingDatagramSize());
        udpSocket->readDatagram(datagram.data(),datagram.size());
        QDataStream in(&datagram,QIODevice::ReadOnly);
        int messageType;
        in >> messageType;
        QString userName,localHostName,ipAddress,message;
        QString time = QDateTime::currentDateTime().toString("yyyy-MM-dd hh:mm:ss");
        switch(messageType)
        {
            case Message:
                {
                    in >>userName >>localHostName >>ipAddress >>message;
                    ui->textBrowser->setTextColor(Qt::blue);
                    ui->textBrowser->setCurrentFont(QFont("Times New Roman",12));
                    ui->textBrowser->append("[ " +localHostName+" ] "+ time);
                    ui->textBrowser->append(message);
                    break;
                }
            case NewParticipant:
                {
                    in >>userName >>localHostName >>ipAddress;
                    newParticipant(userName,localHostName,ipAddress);

                    break;
                }
            case ParticipantLeft:
                {
                    in >>userName >>localHostName;
                    participantLeft(userName,localHostName,time);
                    break;
                }
        case FileName:
            {
                in >>userName >>localHostName >> ipAddress;
                QString clientAddress,fileName;
                in >> clientAddress >> fileName;
                hasPendingFile(userName,ipAddress,clientAddress,fileName);
                break;
            }
        case Refuse:
            {
                in >> userName >> localHostName;
                QString serverAddress;
                in >> serverAddress;            
                QString ipAddress = getIP();

                if(ipAddress == serverAddress)
                {
                    server->refused();
                }
                break;
            }
        case Xchat:
            {
                in >>userName >>localHostName >>ipAddress;
                showxchat(localHostName,ipAddress);//显示与主机名聊天中，不是用户名
                break;
            }
        }
    }
}

//处理新用户加入
void Widget::newParticipant(QString userName,QString localHostName,QString ipAddress)
{
    bool bb = ui->tableWidget->findItems(localHostName,Qt::MatchExactly).isEmpty();
    if(bb)
    {
        QTableWidgetItem *user = new QTableWidgetItem(userName);
        QTableWidgetItem *host = new QTableWidgetItem(localHostName);
        QTableWidgetItem *ip = new QTableWidgetItem(ipAddress);
        ui->tableWidget->insertRow(0);
        ui->tableWidget->setItem(0,0,user);
        ui->tableWidget->setItem(0,1,host);
        ui->tableWidget->setItem(0,2,ip);
        ui->textBrowser->setTextColor(Qt::gray);
        ui->textBrowser->setCurrentFont(QFont("Times New Roman",10));
        ui->textBrowser->append(tr("%1 在线！").arg(localHostName));
        ui->onlineUser->setText(tr("在线人数：%1").arg(ui->tableWidget->rowCount()));
        sendMessage(NewParticipant);
    }
}

//处理用户离开
void Widget::participantLeft(QString userName,QString localHostName,QString time)
{
    int rowNum = ui->tableWidget->findItems(localHostName,Qt::MatchExactly).first()->row();
    ui->tableWidget->removeRow(rowNum);
    ui->textBrowser->setTextColor(Qt::gray);
    ui->textBrowser->setCurrentFont(QFont("Times New Roman",10));
    ui->textBrowser->append(tr("%1 于 %2 离开！").arg(localHostName).arg(time));
    ui->onlineUser->setText(tr("在线人数：%1").arg(ui->tableWidget->rowCount()));
}

Widget::~Widget()
{
    delete ui;
//    delete privatechat;
//    privatechat = NULL;
    //udpSocket
    //server
}

void Widget::changeEvent(QEvent *e)
{
    QWidget::changeEvent(e);
    switch (e->type()) {
    case QEvent::LanguageChange:
        ui->retranslateUi(this);
        break;
    default:
        break;
    }
}

QString Widget::getIP()  //获取ip地址
{
    QList<QHostAddress> list = QNetworkInterface::allAddresses();
    foreach (QHostAddress address, list)
    {
       if(address.protocol() == QAbstractSocket::IPv4Protocol) //我们使用IPv4地址
            return address.toString();
    }
       return 0;
}

void Widget::sendMessage(MessageType type, QString serverAddress)  //发送信息
{
    QByteArray data;
    QDataStream out(&data,QIODevice::WriteOnly);
    QString localHostName = QHostInfo::localHostName();
    QString address = getIP();
    out << type << getUserName() << localHostName;


    switch(type)
    {
        case ParticipantLeft:
            {
                break;
            }
        case NewParticipant:
            {         
                out << address;
                break;
            }

        case Message :
            {
                if(ui->textEdit->toPlainText() == "")
                {
                    QMessageBox::warning(0,tr("警告"),tr("发送内容不能为空"),QMessageBox::Ok);
                    return;
                }
               out << address << getMessage();
               ui->textBrowser->verticalScrollBar()->setValue(ui->textBrowser->verticalScrollBar()->maximum());
               break;

            }
        case FileName:
            {
                int row = ui->tableWidget->currentRow();
                QString clientAddress = ui->tableWidget->item(row,2)->text();
                out << address << clientAddress << fileName;
                break;
            }
        case Refuse:
            {
                out << serverAddress;
                break;
            }
    }
    udpSocket->writeDatagram(data,data.length(),QHostAddress::Broadcast, port);

}

QString Widget::getUserName()  //获取用户名
{
    QStringList envVariables;
    envVariables << "USERNAME.*" << "USER.*" << "USERDOMAIN.*"
                 << "HOSTNAME.*" << "DOMAINNAME.*";
    QStringList environment = QProcess::systemEnvironment();
    foreach (QString string, envVariables)
    {
        int index = environment.indexOf(QRegExp(string));
        if (index != -1)
        {

            QStringList stringList = environment.at(index).split('=');
            if (stringList.size() == 2)
            {
                return stringList.at(1);
                break;
            }
        }
    }
    return false;
}

QString Widget::getMessage()  //获得要发送的信息
{
    QString msg = ui->textEdit->toHtml();

    ui->textEdit->clear();
    ui->textEdit->setFocus();
    return msg;
}

void Widget::closeEvent(QCloseEvent *)
{
    sendMessage(ParticipantLeft);
}

void Widget::sentFileName(QString fileName)
{
    this->fileName = fileName;
    sendMessage(FileName);
}

void Widget::hasPendingFile(QString userName,QString serverAddress,  //接收文件
                            QString clientAddress,QString fileName)
{
    QString ipAddress = getIP();
    if(ipAddress == clientAddress)
    {
        int btn = QMessageBox::information(this,tr("接受文件"),
                                 tr("来自%1(%2)的文件：%3,是否接收？")
                                 .arg(userName).arg(serverAddress).arg(fileName),
                                 QMessageBox::Yes,QMessageBox::No);
        if(btn == QMessageBox::Yes)
        {
            QString name = QFileDialog::getSaveFileName(0,tr("保存文件"),fileName);
            if(!name.isEmpty())
            {
                TcpClient *client = new TcpClient(this);
                client->setFileName(name);
                client->setHostAddress(QHostAddress(serverAddress));
                client->show();

            }

        }
        else{
            sendMessage(Refuse,serverAddress);
        }
    }
}

void Widget::on_send_clicked()//发送
{
    sendMessage(Message);
}

void Widget::on_sendfile_clicked()
{
    if(ui->tableWidget->selectedItems().isEmpty())
    {
        QMessageBox::warning(0,tr("选择用户"),tr("请先从用户列表选择要传送的用户！"),QMessageBox::Ok);
        return;
    }
    server->show();
    server->initServer();
}

void Widget::on_close_clicked()//关闭
{
    this->close();
}

bool Widget::eventFilter(QObject *target, QEvent *event)
{
    if(target == ui->textEdit)
    {
        if(event->type() == QEvent::KeyPress)//回车键
        {
             QKeyEvent *k = static_cast<QKeyEvent *>(event);
             if(k->key() == Qt::Key_Return)
             {
                 on_send_clicked();
                 return true;
             }
        }
    }
    return QWidget::eventFilter(target,event);
}

void Widget::on_fontComboBox_currentFontChanged(QFont f)//字体设置
{
    ui->textEdit->setCurrentFont(f);
    ui->textEdit->setFocus();
}

//字体大小设置
void Widget::on_fontsizecomboBox_currentIndexChanged(QString size)
{
   ui->textEdit->setFontPointSize(size.toDouble());
   ui->textEdit->setFocus();
}

void Widget::on_textbold_clicked(bool checked)
{
    if(checked)
        ui->textEdit->setFontWeight(QFont::Bold);
    else
        ui->textEdit->setFontWeight(QFont::Normal);
    ui->textEdit->setFocus();
}

void Widget::on_textitalic_clicked(bool checked)
{
    ui->textEdit->setFontItalic(checked);
    ui->textEdit->setFocus();
}

void Widget::on_textUnderline_clicked(bool checked)
{
    ui->textEdit->setFontUnderline(checked);
    ui->textEdit->setFocus();
}

void Widget::on_textcolor_clicked()
{
    color = QColorDialog::getColor(color,this);
    if(color.isValid())
    {
        ui->textEdit->setTextColor(color);
        ui->textEdit->setFocus();
    }
}

void Widget::on_save_clicked()//保存聊天记录
{
    if(ui->textBrowser->document()->isEmpty())
        QMessageBox::warning(0,tr("警告"),tr("聊天记录为空，无法保存！"),QMessageBox::Ok);
    else
    {
       //获得文件名,注意getSaveFileName函数的格式即可
       QString fileName = QFileDialog::getSaveFileName(this,tr("保存聊天记录"),tr("聊天记录"),tr("文本(*.txt);;All File(*.*)"));
       if(!fileName.isEmpty())
           saveFile(fileName);
    }
}

bool Widget::saveFile(const QString &fileName)//保存文件
{
    QFile file(fileName);
    if(!file.open(QFile::WriteOnly | QFile::Text))

    {
        QMessageBox::warning(this,tr("保存文件"),
        tr("无法保存文件 %1:\n %2").arg(fileName)
        .arg(file.errorString()));
        return false;
    }
    QTextStream out(&file);
    out << ui->textBrowser->toPlainText();

    return true;
}

void Widget::on_clear_clicked()//清空聊天记录
{
    ui->textBrowser->clear();
}


void Widget::on_tableWidget_doubleClicked(QModelIndex index)
{
    if(ui->tableWidget->item(index.row(),0)->text() == getUserName() &&
        ui->tableWidget->item(index.row(),2)->text() == getIP())
    {
        QMessageBox::warning(0,tr("警告"),tr("你不可以跟自己聊天！！！"),QMessageBox::Ok);
    }
    else
    {
    //    else
        if(!privatechat){
      //  chat *privatechatTemp;
        privatechat = new chat(ui->tableWidget->item(index.row(),1)->text(), //接收主机名
                               ui->tableWidget->item(index.row(),2)->text()) ;//接收用户IP
        }
//        if( privatechat->is_opened )delete privatechat;//如果其曾经显示过则删除掉
        QByteArray data;
        QDataStream out(&data,QIODevice::WriteOnly);
        QString localHostName = QHostInfo::localHostName();
        QString address = getIP();
        out << Xchat << getUserName() << localHostName << address;
        udpSocket->writeDatagram(data,data.length(),QHostAddress::QHostAddress(ui->tableWidget->item(index.row(),2)->text()), port);

//        privatechat->xchat->writeDatagram(data,data.length(),QHostAddress::QHostAddress(ui->tableWidget->item(index.row(),2)->text()), 45456);
      //  if(!privatechat->is_opened)
            privatechat->show();
        privatechat->is_opened = true;
    //    (privatechat->a) = 0;
    }

}

void Widget::showxchat(QString name, QString ip)
{
//    if(!privatechat){
 // chat *privatechatTemp;
    if(!privatechat1)
    privatechat1 = new chat(name,ip);
//    privatechat = privatechatTemp;}
//    chat privatechat(name,ip);//如果不用new函数，则程序运行时只是闪烁显示一下就没了，因为类的生命周期结束了
//    privatechat->is_opened = false;
 // privatechat->show();
  //privatechat.textBrowser.show();
  //privatechat->is_opened = true;
    bb++;
    //delete privatechat;

}

tcpclient.h:

#ifndef TCPCLIENT_H
#define TCPCLIENT_H

#include <QDialog>
#include <QTcpSocket>
#include <QHostAddress>
#include <QFile>
#include <QTime>
namespace Ui {
    class TcpClient;
}

class TcpClient : public QDialog
{
    Q_OBJECT

public:
    explicit TcpClient(QWidget *parent = 0);
    ~TcpClient();
    void setHostAddress(QHostAddress address);
    void setFileName(QString fileName){localFile = new QFile(fileName);}

protected:
    void changeEvent(QEvent *e);

private:
    Ui::TcpClient *ui;
    QTcpSocket *tcpClient;
    quint16 blockSize;
    QHostAddress hostAddress;
    qint16 tcpPort;

    qint64 TotalBytes;
    qint64 bytesReceived;
    qint64 bytesToReceive;
    qint64 fileNameSize;
    QString fileName;
    QFile *localFile;
    QByteArray inBlock;

    QTime time;

private slots:
    void on_tcpClientCancleBtn_clicked();
    void on_tcpClientCloseBtn_clicked();
    void newConnect();
    void readMessage();
    void displayError(QAbstractSocket::SocketError);
};

#endif // TCPCLIENT_H

tcpclient.cpp:

#include "tcpserver.h"
#include "ui_tcpserver.h"
#include <QTcpSocket>
#include <QFileDialog>
#include <QMessageBox>

TcpServer::TcpServer(QWidget *parent):QDialog(parent),
 ui(new Ui::TcpServer)
{
    ui->setupUi(this);
    this->setFixedSize(350,180);

    tcpPort = 6666;
    tcpServer = new QTcpServer(this);  
    connect(tcpServer,SIGNAL(newConnection()),this,SLOT(sendMessage()));

    initServer();

}

TcpServer::~TcpServer()
{
    delete ui;
}

void TcpServer::changeEvent(QEvent *e)
{
    QDialog::changeEvent(e);
    switch (e->type()) {
    case QEvent::LanguageChange:
        ui->retranslateUi(this);
        break;
    default:
        break;
    }
}

void TcpServer::sendMessage()  //开始发送数据
{
    ui->serverSendBtn->setEnabled(false);
    clientConnection = tcpServer->nextPendingConnection();
    connect(clientConnection,SIGNAL(bytesWritten(qint64)),SLOT(updateClientProgress(qint64)));

    ui->serverStatusLabel->setText(tr("开始传送文件 %1 ！").arg(theFileName));

    localFile = new QFile(fileName);
    if(!localFile->open((QFile::ReadOnly))){//以只读方式打开
        QMessageBox::warning(this,tr("应用程序"),tr("无法读取文件 %1:\n%2").arg(fileName).arg(localFile->errorString()));
        return;
    }
    TotalBytes = localFile->size();
    QDataStream sendOut(&outBlock,QIODevice::WriteOnly);
    sendOut.setVersion(QDataStream::Qt_4_6);
    time.start();  //开始计时
    QString currentFile = fileName.right(fileName.size() - fileName.lastIndexOf('/')-1);
    sendOut<<qint64(0)<<qint64(0)<<currentFile;
    TotalBytes += outBlock.size();
    sendOut.device()->seek(0);
    sendOut<<TotalBytes<<qint64((outBlock.size()-sizeof(qint64)*2));
    bytesToWrite = TotalBytes - clientConnection->write(outBlock);
    qDebug()<<currentFile<<TotalBytes;
    outBlock.resize(0);

}

void TcpServer::updateClientProgress(qint64 numBytes)//更新进度条
{
    bytesWritten += (int)numBytes;
    if(bytesToWrite > 0){
        outBlock = localFile->read(qMin(bytesToWrite,loadSize));
        bytesToWrite -= (int)clientConnection->write(outBlock);
        outBlock.resize(0);
    }
    else{
        localFile->close();
    }
    ui->progressBar->setMaximum(TotalBytes);
    ui->progressBar->setValue(bytesWritten);

   float useTime = time.elapsed();
   double speed = bytesWritten / useTime;
   ui->serverStatusLabel->setText(tr("已发送 %1MB (%2MB/s) \n共%3MB 已用时:%4秒\n估计剩余时间：%5秒")
                                  .arg(bytesWritten / (1024*1024))//已发送
                                  .arg(speed*1000/(1024*1024),0,'f',2)//速度
                                  .arg(TotalBytes / (1024 * 1024))//总大小
                                  .arg(useTime/1000,0,'f',0)//用时
                                  .arg(TotalBytes/speed/1000 - useTime/1000,0,'f',0));//剩余时间

   //num.sprintf("%.1f KB/s", (bytesWritten*1000) / (1024.0*time.elapsed()));
    if(bytesWritten == TotalBytes)
        ui->serverStatusLabel->setText(tr("传送文件 %1 成功").arg(theFileName));

}

void TcpServer::on_serverOpenBtn_clicked()  //打开
{
    fileName = QFileDialog::getOpenFileName(this);
    if(!fileName.isEmpty())
    {
        theFileName = fileName.right(fileName.size() - fileName.lastIndexOf('/')-1);
        ui->serverStatusLabel->setText(tr("要传送的文件为：%1 ").arg(theFileName));
        ui->serverSendBtn->setEnabled(true);
        ui->serverOpenBtn->setEnabled(false);
    }
}

void TcpServer::refused()   //被对方拒绝
{
    tcpServer->close();
    ui->serverStatusLabel->setText(tr("对方拒绝接收！！！"));
}

void TcpServer::on_serverSendBtn_clicked()  //发送
{
    if(!tcpServer->listen(QHostAddress::Any,tcpPort))//开始监听
    {
        qDebug() << tcpServer->errorString();
        close();
        return;
    }

    ui->serverStatusLabel->setText(tr("等待对方接收... ..."));
    emit sendFileName(theFileName);
}

void TcpServer::on_serverCloseBtn_clicked()//退出
{   
    if(tcpServer->isListening())
    {
        tcpServer->close();
        clientConnection->abort();
    }
    this->close();
}

void TcpServer::initServer()//初始化
{
    loadSize = 4*1024;
    TotalBytes = 0;
    bytesWritten = 0;
    bytesToWrite = 0;

    ui->serverStatusLabel->setText(tr("请选择要传送的文件"));
    ui->progressBar->reset();
    ui->serverOpenBtn->setEnabled(true);
    ui->serverSendBtn->setEnabled(false);

    tcpServer->close();

}

tcpserver.h:

#ifndef TCPSERVER_H
#define TCPSERVER_H

#include <QDialog>
#include <QTcpServer>
#include <QFile>
#include <QTime>

namespace Ui {
    class TcpServer;
}

class TcpServer : public QDialog
{
    Q_OBJECT

public:
    explicit TcpServer(QWidget *parent = 0);
    ~TcpServer();
    void refused();

    void initServer();


protected:
    void changeEvent(QEvent *e);

private:
    Ui::TcpServer *ui;
    qint16 tcpPort;
    QTcpServer *tcpServer;
    QString fileName;
    QString theFileName;
    QFile *localFile;

    qint64 TotalBytes;
    qint64 bytesWritten;
    qint64 bytesToWrite;
    qint64 loadSize;
    QByteArray outBlock;//缓存一次发送的数据

    QTcpSocket *clientConnection;

    QTime time;//计时器

private slots:
    void on_serverSendBtn_clicked();
    void on_serverCloseBtn_clicked();
    void on_serverOpenBtn_clicked();
    void sendMessage();

   void updateClientProgress(qint64 numBytes);
signals:
    void sendFileName(QString fileName);

};

#endif // TCPSERVER_H

tcpserver.cpp:

#include "tcpserver.h"
#include "ui_tcpserver.h"
#include <QTcpSocket>
#include <QFileDialog>
#include <QMessageBox>

TcpServer::TcpServer(QWidget *parent):QDialog(parent),
 ui(new Ui::TcpServer)
{
    ui->setupUi(this);
    this->setFixedSize(350,180);

    tcpPort = 6666;
    tcpServer = new QTcpServer(this);  
    connect(tcpServer,SIGNAL(newConnection()),this,SLOT(sendMessage()));

    initServer();

}

TcpServer::~TcpServer()
{
    delete ui;
}

void TcpServer::changeEvent(QEvent *e)
{
    QDialog::changeEvent(e);
    switch (e->type()) {
    case QEvent::LanguageChange:
        ui->retranslateUi(this);
        break;
    default:
        break;
    }
}

void TcpServer::sendMessage()  //开始发送数据
{
    ui->serverSendBtn->setEnabled(false);
    clientConnection = tcpServer->nextPendingConnection();
    connect(clientConnection,SIGNAL(bytesWritten(qint64)),SLOT(updateClientProgress(qint64)));

    ui->serverStatusLabel->setText(tr("开始传送文件 %1 ！").arg(theFileName));

    localFile = new QFile(fileName);
    if(!localFile->open((QFile::ReadOnly))){//以只读方式打开
        QMessageBox::warning(this,tr("应用程序"),tr("无法读取文件 %1:\n%2").arg(fileName).arg(localFile->errorString()));
        return;
    }
    TotalBytes = localFile->size();
    QDataStream sendOut(&outBlock,QIODevice::WriteOnly);
    sendOut.setVersion(QDataStream::Qt_4_6);
    time.start();  //开始计时
    QString currentFile = fileName.right(fileName.size() - fileName.lastIndexOf('/')-1);
    sendOut<<qint64(0)<<qint64(0)<<currentFile;
    TotalBytes += outBlock.size();
    sendOut.device()->seek(0);
    sendOut<<TotalBytes<<qint64((outBlock.size()-sizeof(qint64)*2));
    bytesToWrite = TotalBytes - clientConnection->write(outBlock);
    qDebug()<<currentFile<<TotalBytes;
    outBlock.resize(0);

}

void TcpServer::updateClientProgress(qint64 numBytes)//更新进度条
{
    bytesWritten += (int)numBytes;
    if(bytesToWrite > 0){
        outBlock = localFile->read(qMin(bytesToWrite,loadSize));
        bytesToWrite -= (int)clientConnection->write(outBlock);
        outBlock.resize(0);
    }
    else{
        localFile->close();
    }
    ui->progressBar->setMaximum(TotalBytes);
    ui->progressBar->setValue(bytesWritten);

   float useTime = time.elapsed();
   double speed = bytesWritten / useTime;
   ui->serverStatusLabel->setText(tr("已发送 %1MB (%2MB/s) \n共%3MB 已用时:%4秒\n估计剩余时间：%5秒")
                                  .arg(bytesWritten / (1024*1024))//已发送
                                  .arg(speed*1000/(1024*1024),0,'f',2)//速度
                                  .arg(TotalBytes / (1024 * 1024))//总大小
                                  .arg(useTime/1000,0,'f',0)//用时
                                  .arg(TotalBytes/speed/1000 - useTime/1000,0,'f',0));//剩余时间

   //num.sprintf("%.1f KB/s", (bytesWritten*1000) / (1024.0*time.elapsed()));
    if(bytesWritten == TotalBytes)
        ui->serverStatusLabel->setText(tr("传送文件 %1 成功").arg(theFileName));

}

void TcpServer::on_serverOpenBtn_clicked()  //打开
{
    fileName = QFileDialog::getOpenFileName(this);
    if(!fileName.isEmpty())
    {
        theFileName = fileName.right(fileName.size() - fileName.lastIndexOf('/')-1);
        ui->serverStatusLabel->setText(tr("要传送的文件为：%1 ").arg(theFileName));
        ui->serverSendBtn->setEnabled(true);
        ui->serverOpenBtn->setEnabled(false);
    }
}

void TcpServer::refused()   //被对方拒绝
{
    tcpServer->close();
    ui->serverStatusLabel->setText(tr("对方拒绝接收！！！"));
}

void TcpServer::on_serverSendBtn_clicked()  //发送
{
    if(!tcpServer->listen(QHostAddress::Any,tcpPort))//开始监听
    {
        qDebug() << tcpServer->errorString();
        close();
        return;
    }

    ui->serverStatusLabel->setText(tr("等待对方接收... ..."));
    emit sendFileName(theFileName);
}

void TcpServer::on_serverCloseBtn_clicked()//退出
{   
    if(tcpServer->isListening())
    {
        tcpServer->close();
        clientConnection->abort();
    }
    this->close();
}

void TcpServer::initServer()//初始化
{
    loadSize = 4*1024;
    TotalBytes = 0;
    bytesWritten = 0;
    bytesToWrite = 0;

    ui->serverStatusLabel->setText(tr("请选择要传送的文件"));
    ui->progressBar->reset();
    ui->serverOpenBtn->setEnabled(true);
    ui->serverSendBtn->setEnabled(false);

    tcpServer->close();

}

chat.h:

#ifndef CHAT_H
#define CHAT_H

#include <QDialog>
#include <QtNetwork>
#include <QtGui>
#include "tcpclient.h"
#include "tcpserver.h"

namespace Ui {
    class chat;
}

enum MessageType
{
    Message,
    NewParticipant,
    ParticipantLeft,
    FileName,
    Refuse,
    Xchat
};

class chat : public QDialog
{
    Q_OBJECT


public:
    ~chat();
//    chat();
    chat(QString pasvusername, QString pasvuserip);
    QString xpasvuserip;
    QString xpasvusername;
    QUdpSocket *xchat;
    qint32 xport;
    void sendMessage(MessageType type,QString serverAddress="");
    quint16 a;
//    static  qint32 is_opened = 0;
    bool is_opened;

public slots:


protected:
    void hasPendingFile(QString userName,QString serverAddress,  //接收文件
                                QString clientAddress,QString fileName);
    void participantLeft(QString userName,QString localHostName,QString time);
    bool eventFilter(QObject *target, QEvent *event); //事件过滤器

private:
    Ui::chat *ui;
    TcpServer *server;
    QColor color;//颜色
    bool saveFile(const QString& fileName);//保存聊天记录
    QString getMessage();
    QString getIP();
    QString getUserName();
    QString message;
    QString fileName;

private slots:
    void sentFileName(QString);
    void on_sendfile_clicked();
    void processPendingDatagrams();
    void on_send_clicked();
    void on_close_clicked();
    void on_clear_clicked();
    void on_save_clicked();
    void on_textcolor_clicked();
    void on_textUnderline_clicked(bool checked);
    void on_textitalic_clicked(bool checked);
    void on_textbold_clicked(bool checked);
    void on_fontComboBox_currentFontChanged(QFont f);
    void on_fontsizecomboBox_currentIndexChanged(QString );
    void currentFormatChanged(const QTextCharFormat &format);

};

#endif // CHAT_H

chat.cpp:

#include "chat.h"
#include "ui_chat.h"

//chat::chat():ui(new Ui::chat)
//{
//    is_opened = false;
//}


chat::chat(QString pasvusername, QString pasvuserip) : ui(new Ui::chat)
{
    ui->setupUi(this);
    ui->textEdit->setFocusPolicy(Qt::StrongFocus);
    ui->textBrowser->setFocusPolicy(Qt::NoFocus);

    ui->textEdit->setFocus();
    ui->textEdit->installEventFilter(this);

    a = 0;
    is_opened = false;
//    this->is_opened = false;
    xpasvusername = pasvusername;
    xpasvuserip = pasvuserip;

    ui->label->setText(tr("与%1聊天中   对方IP:%2").arg(xpasvusername).arg(pasvuserip));

    //UDP部分
    xchat = new QUdpSocket(this);
    xport = 45456;
 //   xchat->bind(xport, QUdpSocket::ShareAddress | QUdpSocket::ReuseAddressHint);
    xchat->bind( QHostAddress::QHostAddress(getIP()), xport );
    connect(xchat, SIGNAL(readyRead()), this, SLOT(processPendingDatagrams()));

    //TCP部分
    server = new TcpServer(this);
    connect(server,SIGNAL(sendFileName(QString)),this,SLOT(sentFileName(QString)));

    connect(ui->textEdit,SIGNAL(currentCharFormatChanged(QTextCharFormat)),this,SLOT(currentFormatChanged(const QTextCharFormat)));
}

chat::~chat()
{
    is_opened = false;
    delete ui;
}

bool chat::eventFilter(QObject *target, QEvent *event)
{
    if(target == ui->textEdit)
    {
        if(event->type() == QEvent::KeyPress)//按下键盘某键
        {
             QKeyEvent *k = static_cast<QKeyEvent *>(event);
             if(k->key() == Qt::Key_Return)//回车键
             {
                 on_send_clicked();
                 return true;
             }
        }
    }
    return QWidget::eventFilter(target,event);
}

//处理用户离开
void chat::participantLeft(QString userName,QString localHostName,QString time)
{
    ui->textBrowser->setTextColor(Qt::gray);
    ui->textBrowser->setCurrentFont(QFont("Times New Roman",10));
    ui->textBrowser->append(tr("%1 于 %2 离开！").arg(userName).arg(time));
}

QString chat::getUserName()  //获取用户名
{
    QStringList envVariables;
    envVariables << "USERNAME.*" << "USER.*" << "USERDOMAIN.*"
                 << "HOSTNAME.*" << "DOMAINNAME.*";
    QStringList environment = QProcess::systemEnvironment();
    foreach (QString string, envVariables)
    {
        int index = environment.indexOf(QRegExp(string));
        if (index != -1)
        {

            QStringList stringList = environment.at(index).split('=');
            if (stringList.size() == 2)
            {
                return stringList.at(1);
                break;
            }
        }
    }
    return false;
}

QString chat::getIP()  //获取ip地址
{
    QList<QHostAddress> list = QNetworkInterface::allAddresses();
    foreach (QHostAddress address, list)
    {
       if(address.protocol() == QAbstractSocket::IPv4Protocol) //我们使用IPv4地址
            return address.toString();
    }
       return 0;
}

void chat::hasPendingFile(QString userName,QString serverAddress,  //接收文件
                            QString clientAddress,QString fileName)
{
    QString ipAddress = getIP();
    if(ipAddress == clientAddress)
    {
        int btn = QMessageBox::information(this,tr("接受文件"),
                                 tr("来自%1(%2)的文件：%3,是否接收？")
                                 .arg(userName).arg(serverAddress).arg(fileName),
                                 QMessageBox::Yes,QMessageBox::No);
        if(btn == QMessageBox::Yes)
        {
            QString name = QFileDialog::getSaveFileName(0,tr("保存文件"),fileName);
            if(!name.isEmpty())
            {
                TcpClient *client = new TcpClient(this);
                client->setFileName(name);
                client->setHostAddress(QHostAddress(serverAddress));
                client->show();

            }

        }
        else{
            sendMessage(Refuse,serverAddress);
        }
    }
}

void chat::processPendingDatagrams()   //接收数据UDP
{
    while(xchat->hasPendingDatagrams())
    {
        QByteArray datagram;
        datagram.resize(xchat->pendingDatagramSize());
        xchat->readDatagram(datagram.data(),datagram.size());
        QDataStream in(&datagram,QIODevice::ReadOnly);
        int messageType;
        in >> messageType;
        QString userName,localHostName,ipAddress,messagestr;
        QString time = QDateTime::currentDateTime().toString("yyyy-MM-dd hh:mm:ss");
        switch(messageType)
        {
            case Xchat:
            {
//                ui.show();
                break;
            }
            case Message:
                {
                    //这2条语句都没有用。why？？、
                    /*this->hide();
                    this->close();*/
                    in >>userName >>localHostName >>ipAddress >>messagestr;
                    ui->textBrowser->setTextColor(Qt::blue);
                    ui->textBrowser->setCurrentFont(QFont("Times New Roman",12));
                    ui->textBrowser->append("[ " +localHostName+" ] "+ time);//与主机名聊天中
                    ui->textBrowser->append(messagestr);
            //        ui->textBrowser->show();
                    //this->textBrowser->setTextColor(Qt::blue);
                    //this->textBrowser->setCurrentFont(QFont("Times New Roman",12));
                    //this->textBrowser->append("[ " +localHostName+" ] "+ time);//与主机名聊天中
                    //this->textBrowser->append(messagestr);
            
            //        a ++;
            //        if( is_opened == false )//加了这句，接收端B不显示端口了
                    {
                        this->show();////解决bug1.收到私聊消息后才显示
                //        ui->textBrowser->show();
                    //    this->show();
                //        ui->textBrowser->show();
                    //    ui.show();
                    //    if( this->show() )
                //        this->hide();
                //        0 == a;
                        is_opened = true;
                    }
                    break;
                }
        case FileName:
            {
                in >>userName >>localHostName >> ipAddress;
                QString clientAddress,fileName;
                in >> clientAddress >> fileName;
                hasPendingFile(userName,ipAddress,clientAddress,fileName);
                break;
            }
        case Refuse:
            {
                in >> userName >> localHostName;
                QString serverAddress;
                in >> serverAddress;
                QString ipAddress = getIP();

                if(ipAddress == serverAddress)
                {
                    server->refused();
                }
                break;
            }
        case ParticipantLeft:
            {
                in >>userName >>localHostName;
                participantLeft(userName,localHostName,time);
                QMessageBox::information(0,tr("本次对话关闭"),tr("对方结束了对话"),QMessageBox::Ok);
                a = 1;
                ui->textBrowser->clear();
                //is_opened = true;
            //    this->is_opened = false;
                ui->~chat();
                close();
            //    delete ui;
            //    ui = 0;
                break;
            }
        }
    }
}

void chat::sentFileName(QString fileName)
{
    this->fileName = fileName;
    sendMessage(FileName);
}

QString chat::getMessage()  //获得要发送的信息
{
    QString msg = ui->textEdit->toHtml();
    qDebug()<<msg;
    ui->textEdit->clear();
    ui->textEdit->setFocus();
    return msg;
}

//通过私聊套接字发送到对方的私聊专用端口上
void chat::sendMessage(MessageType type , QString serverAddress)  //发送信息
{
    QByteArray data;
    QDataStream out(&data,QIODevice::WriteOnly);
    QString localHostName = QHostInfo::localHostName();
    QString address = getIP();
    out << type << getUserName() << localHostName;


    switch(type)
    {
    case ParticipantLeft:
        {
            break;
        }
    case Message :
        {
            if(ui->textEdit->toPlainText() == "")
            {
                QMessageBox::warning(0,tr("警告"),tr("发送内容不能为空"),QMessageBox::Ok);
                return;
            }
            message = getMessage();
            out << address << message;
            ui->textBrowser->verticalScrollBar()->setValue(ui->textBrowser->verticalScrollBar()->maximum());
            break;
        }
    case FileName:
            {
                QString clientAddress = xpasvuserip;
                out << address << clientAddress << fileName;
                break;
            }
    case Refuse:
            {
                out << serverAddress;
                break;
            }
    }
    xchat->writeDatagram(data,data.length(),QHostAddress::QHostAddress(xpasvuserip), 45456);

}

void chat::currentFormatChanged(const QTextCharFormat &format)
{//当编辑器的字体格式改变时，我们让部件状态也随之改变
    ui->fontComboBox->setCurrentFont(format.font());

    if(format.fontPointSize()<9)  //如果字体大小出错，因为我们最小的字体为9
    {
        ui->fontsizecomboBox->setCurrentIndex(3); //即显示12
    }
    else
    {
        ui->fontsizecomboBox->setCurrentIndex(ui->fontsizecomboBox->findText(QString::number(format.fontPointSize())));

    }

    ui->textbold->setChecked(format.font().bold());
    ui->textitalic->setChecked(format.font().italic());
    ui->textUnderline->setChecked(format.font().underline());
    color = format.foreground().color();
}

void chat::on_fontComboBox_currentFontChanged(QFont f)//字体设置
{
    ui->textEdit->setCurrentFont(f);
    ui->textEdit->setFocus();
}

void chat::on_fontsizecomboBox_currentIndexChanged(QString size)
{
   ui->textEdit->setFontPointSize(size.toDouble());
   ui->textEdit->setFocus();
}

void chat::on_textbold_clicked(bool checked)
{
    if(checked)
        ui->textEdit->setFontWeight(QFont::Bold);
    else
        ui->textEdit->setFontWeight(QFont::Normal);
    ui->textEdit->setFocus();
}

void chat::on_textitalic_clicked(bool checked)
{
    ui->textEdit->setFontItalic(checked);
    ui->textEdit->setFocus();
}

void chat::on_save_clicked()//保存聊天记录
{
    if(ui->textBrowser->document()->isEmpty())
        QMessageBox::warning(0,tr("警告"),tr("聊天记录为空，无法保存！"),QMessageBox::Ok);
    else
    {
       //获得文件名
       QString fileName = QFileDialog::getSaveFileName(this,tr("保存聊天记录"),tr("聊天记录"),tr("文本(*.txt);;All File(*.*)"));
       if(!fileName.isEmpty())
           saveFile(fileName);
    }
}

void chat::on_clear_clicked()//清空聊天记录
{
    ui->textBrowser->clear();
}

bool chat::saveFile(const QString &fileName)//保存文件
{
    QFile file(fileName);
    if(!file.open(QFile::WriteOnly | QFile::Text))

    {
        QMessageBox::warning(this,tr("保存文件"),
        tr("无法保存文件 %1:\n %2").arg(fileName)
        .arg(file.errorString()));
        return false;
    }
    QTextStream out(&file);
    out << ui->textBrowser->toPlainText();

    return true;
}

void chat::on_textUnderline_clicked(bool checked)
{
    ui->textEdit->setFontUnderline(checked);
    ui->textEdit->setFocus();
}

void chat::on_textcolor_clicked()
{
    color = QColorDialog::getColor(color,this);
    if(color.isValid())
    {
        ui->textEdit->setTextColor(color);
        ui->textEdit->setFocus();
    }
}



void chat::on_close_clicked()
{
    sendMessage(ParticipantLeft);
    a = 1;
    ui->textBrowser->clear();
    //is_opened = true;
//    this->is_opened = false;
    close();
    ui->~chat();

    //this->close();
    /*delete ui;
    ui = 0;*/
    
}

void chat::on_send_clicked()
{
    sendMessage(Message);
    QString localHostName = QHostInfo::localHostName();
    QString time = QDateTime::currentDateTime().toString("yyyy-MM-dd hh:mm:ss");
    ui->textBrowser->setTextColor(Qt::blue);
    ui->textBrowser->setCurrentFont(QFont("Times New Roman",12));
    ui->textBrowser->append("[ " +localHostName+" ] "+ time);
    ui->textBrowser->append(message);
//    is_opened = true;
}

void chat::on_sendfile_clicked()
{
    server->show();
    server->initServer();
}

main:

#include <QtGui/QApplication>
#include "widget.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    QTextCodec::setCodecForTr(QTextCodec::codecForLocale());
    w.show();
    return a.exec();
}

　　参考资料：

http://www.yafeilinux.com/

　　附录：

　　实验工程code下载。

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原文地址：https://www.cnblogs.com/tornadomeet/p/2576355.html