Qt中的网络编程（Tcp和Udp）详解及实现

Qt中的网络编程（Tcp和Udp）详解及实现
代码卡的格式不对，看我的代码标题去拷贝，共四个文件。

1、安装qty软件，官网直接下载在线安装。怕以后麻烦直接安装选择一个完整版本QT勾选。在线下载i30多g应该，官网默认下载半天最少了。可以给参数来源于国内源，在线就快到半小时搞定
2、qt 信号和槽机制自动：双击按钮啥的UI控件，然后就会自动添加槽函数原型，自己写要显示的东西就行
如果信号和槽机制手动：用Qt connect。格式：connect（&sender，&CLASSA::signal，&receiver ，&CLASSB:: slot, Qt::连接方式);
3、 Qt TCP网络上位机的设计

分为客户端和服务端端，要分别打开一个QT建设项目：
新建工程-都选择 QWidget 程序-qmake-默认-完成。

两个pro：添加 QT += network，引入模块。
分别在 mainwindow.ui 中画图，根据窗口的按钮、文本框等元素去画图。并修改UI元素的

4、分别修改两个工程的两个文件
mainwindow.h
mainwindow.cpp
内容直接拷贝：
客户端：mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include

#include
#include
#include

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
MainWindow(QWidget *parent = nullptr);
~MainWindow();

private:
Ui::MainWindow *ui;

private:
QTcpSocket *tcpclient; // 客户端tcpclient
QString getlocalip(); // 获取本机IP地址

protected:
void closeEvent(QCloseEvent *event);

private slots:
void connectfunc();
void disconnectfunc();
void socketreaddata();

void on_pushButton_Connect_clicked();
void on_pushButton_Send_clicked();
void on_pushButton_Disconnect_clicked();

};
#endif // MAINWINDOW_H
客户端：mainwindow.cpp
#include “mainwindow.h”
#include “ui_mainwindow.h”

MainWindow::MainWindow(QWidget *parent)

QMainWindow(parent)
, ui(new Ui::MainWindow)
{
ui->setupUi(this);

tcpclient=new QTcpSocket(this);QString strip=getlocalip();ui->comboBoxIp->addItem(strip);connect(tcpclient,SIGNAL(connected()),this,SLOT(connectfunc()));
connect(tcpclient,SIGNAL(disconnected()),this,SLOT(disconnectfunc()));
connect(tcpclient,SIGNAL(readyRead()),this,SLOT(socketreaddata()));

}

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

void MainWindow::on_pushButton_Connect_clicked()
{
QString addr=ui->comboBoxIp->currentText();
quint16 port=ui->spinBoxPort->value();
tcpclient->connectToHost(addr,port);
}

void MainWindow::on_pushButton_Send_clicked()
{
QString strmsg=ui->lineEdit_InputMsg->toPlainText();
ui->plainTextEdit_DispMsg->setPlainText(“[out]:”+strmsg);
ui->lineEdit_InputMsg->clear();

QByteArray str=strmsg.toUtf8();
str.append('\n');
tcpclient->write(str);

}

void MainWindow::on_pushButton_Disconnect_clicked()
{
if(tcpclient->state()==QAbstractSocket::ConnectedState)
tcpclient->disconnectFromHost();
}

QString MainWindow::getlocalip() // 获取本机IP地址
{
QString hostname=QHostInfo::localHostName();
QHostInfo hostinfo=QHostInfo::fromName(hostname);

QString localip="";QList<QHostAddress> addlist=hostinfo.addresses();
if(!addlist.isEmpty())
{for (int i=0;i<addlist.count();i++){QHostAddress ahost=addlist.at(i);if(QAbstractSocket::IPv4Protocol==ahost.protocol()){localip=ahost.toString();break;}}
}return localip;

}

void MainWindow::closeEvent(QCloseEvent *event)
{
if(tcpclient->state()==QAbstractSocket::ConnectedState)
{
tcpclient->disconnectFromHost();
}
// event->accept();

}

void MainWindow::connectfunc()
{
ui->plainTextEdit_DispMsg->setPlainText(“已经连接到服务器端”);
ui->plainTextEdit_DispMsg->setPlainText(“**********peer address:”+
tcpclient->peerAddress().toString());
ui->plainTextEdit_DispMsg->setPlainText(“**********peer port:”+
QString::number(tcpclient->peerPort()));

ui->pushButton_Connect->setEnabled(false);
ui->pushButton_Disconnect->setEnabled(true);

}
void MainWindow::disconnectfunc()
{
ui->plainTextEdit_DispMsg->setPlainText(“已断开与服务器端的连接”);

ui->pushButton_Connect->setEnabled(true);
ui->pushButton_Disconnect->setEnabled(false);

}
void MainWindow::socketreaddata()
{
while(tcpclient->canReadLine())
ui->plainTextEdit_DispMsg->setPlainText(“[in]:”+tcpclient->readLine());

}

服务器端：mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include

#include // 专门用于建立TCP连接并传输数据信息
#include // 此模块提供开发TCP/IP客户端和服务器的类

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
MainWindow(QWidget *parent = nullptr);
~MainWindow();

private:
Ui::MainWindow *ui;

// 自定义如下

private:
QTcpServer *tcpserver; //TCP服务器
QTcpSocket *tcpsocket;// TCP通讯socket
QString GetLocalIpAddress(); // 获取本机的IP地址

private slots:
void clientconnect();
void clientdisconnect();
void socketreaddata();
void newconnection();

void on_pushButton_Start_clicked();
void on_pushButton_Stop_clicked();
void on_pushButton_Send_clicked();

protected:
void closeEvent(QCloseEvent *event);

};
#endif // MAINWINDOW_H
服务器端：mainwindow.cpp
#include “mainwindow.h”
#include “ui_mainwindow.h”
#include
#include

MainWindow::MainWindow(QWidget *parent)

QMainWindow(parent)
, ui(new Ui::MainWindow)
{
ui->setupUi(this);

QString strip=GetLocalIpAddress();
// QMessageBox::information(this,"数据",strip,QMessageBox::Yes);ui->comboBoxIp->addItem(strip);tcpserver=new QTcpServer(this);connect(tcpserver,SIGNAL(newConnection()),this,SLOT(newconnection()));

}

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

void MainWindow::on_pushButton_Start_clicked()
{
QString ip=ui->comboBoxIp->currentText();
quint16 port=ui->spinBoxPort->value();

QHostAddress address(ip);
tcpserver->listen(address,port);ui->plainTextEdit_DispMsg->setPlainText("$$$$$$$$$$开始监听$$$$$$$$$$");
ui->plainTextEdit_DispMsg->setPlainText("$$$$$$$$$$服务器地址$$$$$$$$$$："+tcpserver->serverAddress().toString());
ui->plainTextEdit_DispMsg->setPlainText("$$$$$$$$$$服务器端口$$$$$$$$$$："+QString::number(tcpserver->serverPort()));
ui->pushButton_Start->setEnabled(false);
ui->pushButton_Stop->setEnabled(true);

}

void MainWindow::on_pushButton_Stop_clicked()
{
if(tcpserver->isListening())
{
tcpserver->close();
ui->pushButton_Start->setEnabled(true);
ui->pushButton_Stop->setEnabled(false);
}

}

void MainWindow::on_pushButton_Send_clicked()
{
QString strmsg=ui->lineEdit_InputMsg->toPlainText();

ui->plainTextEdit_DispMsg->setPlainText("[out]:"+strmsg);ui->lineEdit_InputMsg->clear();QByteArray str=strmsg.toUtf8();
str.append("\n");
tcpsocket->write(str);

}

QString MainWindow::GetLocalIpAddress() // 获取本机的IP地址
{
QString hostname=QHostInfo::localHostName();
QHostInfo hostinfo=QHostInfo::fromName(hostname);

QString localip="";QList<QHostAddress> addresslist=hostinfo.addresses();if(!addresslist.isEmpty())
{for (int i=0;i<addresslist.count();i++){QHostAddress addrhost=addresslist.at(i);if(QAbstractSocket::IPv4Protocol==addrhost.protocol()){localip=addrhost.toString();break;}}
}return localip;

}

void MainWindow::clientconnect()
{
// 客户端连接
ui->plainTextEdit_DispMsg->setPlainText(“客户端socket连接”);
ui->plainTextEdit_DispMsg->setPlainText(“**********peer address:”+
tcpsocket->peerAddress().toString());
ui->plainTextEdit_DispMsg->setPlainText(“**********peer port:”+
QString::number(tcpsocket->peerPort()));

}

void MainWindow::clientdisconnect()
{
// 客户端断开连接
ui->plainTextEdit_DispMsg->setPlainText(“客户端socket断开连接”);
tcpsocket->deleteLater();

}

void MainWindow::socketreaddata()
{
// 读取数据
while(tcpsocket->canReadLine())
ui->plainTextEdit_DispMsg->setPlainText(“[in]”+tcpsocket->readLine());

}

void MainWindow::newconnection()
{
tcpsocket=tcpserver->nextPendingConnection();

connect(tcpsocket,SIGNAL(connected()),this,SLOT(clientconnect()));
clientconnect();connect(tcpsocket,SIGNAL(disconnected()),this,SLOT(clientdisconnect()));connect(tcpsocket,SIGNAL(readyRead()),this,SLOT(socketreaddata()));connect(tcpsocket,SIGNAL(stateChanged(QAbstractSocket::SocketState)),this,SLOT(OnSocketStateChanged(QAbstractSocket::SocketState)));

}

void MainWindow::closeEvent(QCloseEvent *event)
{
if(tcpserver->isListening())
tcpserver->close();