• 【无标题】

    客户端每隔10ms向服务器发送一次数字字符串，从0开始。

    1. #ifndef MAINWINDOW_H
    2. #define MAINWINDOW_H
    3.  
    4. #include 
    5. #include  
    6. #include  
    7. #include 
    8. namespace Ui {
    9. class MainWindow;
    10. }
    11.  
    12. class MainWindow : public QMainWindow
    13. {
    14.     Q_OBJECT
    15. private:
    16.     QTcpSocket  *tcpClient;  //socket
    17.     QLabel  *LabSocketState;  //状态栏显示标签
    18.  
    19.     QString getLocalIP();//获取本机IP地址
    20. protected:
    21.     void    closeEvent(QCloseEvent *event);
    22. public:
    23.     explicit MainWindow(QWidget *parent = 0);
    24.     ~MainWindow();
    25.  
    26. private slots:
    27. //自定义槽函数
    28.     void    onConnected();
    29.     void    onDisconnected();
    30.     void    onSocketStateChange(QAbstractSocket::SocketState socketState);
    31.     void    onSocketReadyRead();//读取socket传入的数据
    32. //
    33.     void on_actConnect_triggered();
    34.  
    35.     void on_actDisconnect_triggered();
    36.  
    37.     void on_actClear_triggered();
    38.  
    39.     void on_pushButton_clicked();
    40.  
    41.     void send_msg();
    42.  
    43. private:
    44.     Ui::MainWindow *ui;
    45.     QTimer* timer;
    46. };
    47.  
    48. #endif // MAINWINDOW_H

    关键：

    QTimer* timer;

    1. #include "mainwindow.h"
    2. #include "ui_mainwindow.h"
    3.  
    4. #include    
    5. #include    
    6. #include    
    7. QString MainWindow::getLocalIP()
    8. {
    9.     QString hostName=QHostInfo::localHostName();//本地主机名
    10.     QHostInfo   hostInfo=QHostInfo::fromName(hostName);
    11.     QString   localIP="";
    12.  
    13.     QList addList=hostInfo.addresses();//
    14.  
    15.     if (!addList.isEmpty())
    16.     for (int i=0;icount();i++)
    17.     {
    18.         QHostAddress aHost=addList.at(i);
    19.         if (QAbstractSocket::IPv4Protocol==aHost.protocol())
    20.         {
    21.             localIP=aHost.toString();
    22.             break;
    23.         }
    24.     }
    25.     return localIP;
    26. }
    27. void MainWindow::closeEvent(QCloseEvent *event)
    28. {
    29.     if (tcpClient->state()==QAbstractSocket::ConnectedState)
    30.         tcpClient->disconnectFromHost();
    31.     event->accept();
    32. }
    33.  
    34. MainWindow::MainWindow(QWidget *parent) :
    35.     QMainWindow(parent),
    36.     ui(new Ui::MainWindow)
    37. {
    38.     ui->setupUi(this);
    39.  
    40.     tcpClient=new QTcpSocket(this); //创建socket变量
    41.  
    42.     timer = new QTimer(this);
    43.     connect(timer, SIGNAL(timeout()), this, SLOT(send_msg()));
    44.  
    45.     LabSocketState=new QLabel("Socket状态：");//状态栏标签
    46.     LabSocketState->setMinimumWidth(250);
    47.     ui->statusBar->addWidget(LabSocketState);
    48.  
    49.     QString localIP=getLocalIP();//本机IP
    50.     this->setWindowTitle(this->windowTitle()+"----本机IP："+localIP);
    51.     ui->comboServer->addItem(localIP);
    52.  
    53.  
    54.     connect(tcpClient,SIGNAL(connected()),this,SLOT(onConnected()));
    55.     connect(tcpClient,SIGNAL(disconnected()),this,SLOT(onDisconnected()));
    56.  
    57.     connect(tcpClient,SIGNAL(stateChanged(QAbstractSocket::SocketState)),
    58.             this,SLOT(onSocketStateChange(QAbstractSocket::SocketState)));
    59.     connect(tcpClient,SIGNAL(readyRead()),
    60.             this,SLOT(onSocketReadyRead()));
    61. }
    62.  
    63. MainWindow::~MainWindow()
    64. {
    65.     delete ui;
    66. }
    67.  
    68. void MainWindow::onConnected()
    69. { //connected()信号槽函数
    70.     ui->plainTextEdit->appendPlainText("**已连接到服务器");
    71.     ui->plainTextEdit->appendPlainText("**peer address:"+
    72.                                    tcpClient->peerAddress().toString());
    73.     ui->plainTextEdit->appendPlainText("**peer port:"+
    74.                                    QString::number(tcpClient->peerPort()));
    75.     ui->actConnect->setEnabled(false);
    76.     ui->actDisconnect->setEnabled(true);
    77. }
    78.  
    79. void MainWindow::onDisconnected()
    80. {//disConnected()信号槽函数
    81.     ui->plainTextEdit->appendPlainText("**已断开与服务器的连接");
    82.     ui->actConnect->setEnabled(true);
    83.     ui->actDisconnect->setEnabled(false);
    84. }
    85.  
    86. void MainWindow::onSocketReadyRead()
    87. {//readyRead()信号槽函数
    88.     while(tcpClient->canReadLine())
    89.         ui->plainTextEdit->appendPlainText("[in] "+tcpClient->readLine());
    90. }
    91.  
    92. void MainWindow::onSocketStateChange(QAbstractSocket::SocketState socketState)
    93. {//stateChange()信号槽函数
    94.     switch(socketState)
    95.     {
    96.     case QAbstractSocket::UnconnectedState:
    97.         LabSocketState->setText("scoket状态：UnconnectedState");
    98.         break;
    99.     case QAbstractSocket::HostLookupState:
    100.         LabSocketState->setText("scoket状态：HostLookupState");
    101.         break;
    102.     case QAbstractSocket::ConnectingState:
    103.         LabSocketState->setText("scoket状态：ConnectingState");
    104.         break;
    105.  
    106.     case QAbstractSocket::ConnectedState:
    107.         LabSocketState->setText("scoket状态：ConnectedState");
    108.         break;
    109.  
    110.     case QAbstractSocket::BoundState:
    111.         LabSocketState->setText("scoket状态：BoundState");
    112.         break;
    113.  
    114.     case QAbstractSocket::ClosingState:
    115.         LabSocketState->setText("scoket状态：ClosingState");
    116.         break;
    117.  
    118.     case QAbstractSocket::ListeningState:
    119.         LabSocketState->setText("scoket状态：ListeningState");
    120.     }
    121. }
    122.  
    123. void MainWindow::on_actConnect_triggered()
    124. {//连接到服务器
    125.     QString     addr=ui->comboServer->currentText();
    126.     quint16     port=ui->spinPort->value();
    127.     tcpClient->connectToHost(addr,port);
    128. //    tcpClient->connectToHost(QHostAddress::LocalHost,port);
    129.  
    130.     
    131. }
    132.  
    133. void MainWindow::on_actDisconnect_triggered()
    134. {//断开与服务器的连接
    135.     if (tcpClient->state()==QAbstractSocket::ConnectedState)
    136.         tcpClient->disconnectFromHost();
    137. }
    138.  
    139. void MainWindow::on_actClear_triggered()
    140. {
    141.     ui->plainTextEdit->clear();
    142. }
    143.  
    144. void MainWindow::on_pushButton_clicked()
    145. {
    146.     timer->start(10);
    147. }
    148. void MainWindow::send_msg()
    149. {
    150.     static int m = 0;
    151.     QString msg = QString::number(m);
    152.  
    153.     ui->plainTextEdit->appendPlainText("[out] " + msg);
    154.  
    155.     QByteArray  str = msg.toUtf8();
    156.     str.append('\n');
    157.     tcpClient->write(str);
    158.  
    159.     m++;
    160. }

    关键：

    1.     timer = new QTimer(this);
    2.     connect(timer, SIGNAL(timeout()), this, SLOT(send_msg()));
    1. void MainWindow::on_pushButton_clicked()
    2. {
    3.     timer->start(10);
    4. }
    5. void MainWindow::send_msg()
    6. {
    7.     static int m = 0;
    8.     QString msg = QString::number(m);
    9.  
    10.     ui->plainTextEdit->appendPlainText("[out] " + msg);
    11.  
    12.     QByteArray  str = msg.toUtf8();
    13.     str.append('\n');
    14.     tcpClient->write(str);
    15.  
    16.     m++;
    17. }

    修改：

    1. void MainWindow::on_pushButton_clicked()
    2. {
    3.     timer->start(1);
    4. }

    客户端每1ms向服务器发送一个数字，此时也可以。

    如果客户端中:

    1.     while (1)
    2.     {
    3.         QString msg = QString::number(1);
    4.  
    5.         //ui->plainTextEdit->appendPlainText("[out] " + msg);
    6.         qDebug() << "[out] " + msg;
    7.         QByteArray  str = msg.toUtf8();
    8.         str.append('\n');
    9.         tcpClient->write(str);
    10.     }

    不断向服务器发送信息，此时页面是卡到一点都动不了，所以需要使用多线程来处理。

     一种错误的写法：

    1. #include "workThread.h"
    2. #include 
    3. #include 
    4. #include 
    5.  
    6. workThread::workThread(QTcpSocket* tcpClient,QObject *parent)
    7. 	: QThread(parent)
    8. {
    9.    qDebug()<<"workThread::workThread" << QThread::currentThread();
    10.    this->tcpClient = tcpClient;
    11.    timer = new QTimer(this);
    12.    connect(timer, &QTimer::timeout, this, [=]() {
    13.        ok = false;
    14.        });
    15.    timer->start(1000);
    16. }
    17.  
    18. workThread::~workThread()
    19. {
    20. }
    21. void workThread::run()
    22. {
    23.     qDebug() <<"run():" << QThread::currentThread();
    24.     send_msg();
    25. }
    26. void workThread::send_msg()
    27. {
    28.     qDebug() <<"send_msg():" << QThread::currentThread();
    29.     while (1)
    30.     {
    31.         QString msg = QString::number(1);
    32.         if (ok == false) {
    33.             qDebug() << "[out] " + msg;
    34.             ok = true;
    35.         }
    36.         QByteArray  str = msg.toUtf8();
    37.         str.append('\n');
    38.         tcpClient->write(str);
    39.     }
    40. }

    workThread::workThread QThread(0xbde160)
    run(): workThread(0xc744b0)
    send_msg(): workThread(0xc744b0)
    QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread

    QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread报错-CSDN博客

    1. class workThread  : public QThread
    2. {
    3. 	Q_OBJECT
    4. signals:
    5.  
    6. public:
    7. 	workThread(QObject *parent);
    8. 	~workThread();
    9. protected:
    10. 	void run();
    11. private:
    12. 	QTcpSocket* tcpClient;  //socket
    13. };
    1. void workThread::run()
    2. {
    3.     qDebug() <<"run():" << QThread::currentThread();
    4.     tcpClient = new QTcpSocket(this); //创建socket变量
    5.  
    6. }

    这样写会导致：

     QObject: Cannot create children for a parent that is in a different thread.
    (Parent is workThread(0xc194f0), parent's thread is QThread(0xb7f940), current thread is workThread(0xc194f0)

     关键在这句：

    tcpClient = new QTcpSocket(this); //创建socket变量

    this是主线程（0xb7f940）的，而当前线程是子线程(0xc194f0)。

    tcpClient是子线程的(0xc194f0)。

    不允许出现，父亲(this)与孩子(tcpClient)是不同线程的对象，这样的情况。

    可以这样写：

    1. void workThread::run()
    2. {
    3.     qDebug() <<"run():" << QThread::currentThread();
    4.     tcpClient = new QTcpSocket; //创建socket变量
    5. }

    另一种错误写法：

    1. void workThread::run()
    2. {
    3.     qDebug() <<"run():" << QThread::currentThread();
    4.     tcpClient = new QTcpSocket; //创建socket变量
    5.     MainWindow* window = (MainWindow*)(parent());
    6.     connect(window, &MainWindow::connectToHost, this, &workThread::connectToHost, Qt::QueuedConnection);
    7.     qDebug() << "......";
    8. }
    9. void workThread::connectToHost(QString addr, quint16 port)
    10. {
    11.     qDebug() << "workThread::connectToHost:" << QThread::currentThread();
    12.     tcpClient->connectToHost(addr, port);
    13. }

    run(): workThread(0x108f510)
    ......
    workThread::connectToHost: QThread(0x100fa30)
    QObject: Cannot create children for a parent that is in a different thread.
    (Parent is QTcpSocket(0x109c458), parent's thread is workThread(0x108f510), current thread is QThread(0x100fa30)

    run()函数：工作线程(0x108f510)

    connectToHost槽函数:主线程(0x100fa30)

    有一个QObject子类对象：假设它的对象名为m。

    它的parent()为QTcpSocket(0x109c458)，QTcpSocket(0x109c458)所在的线程是工作线程(0x108f510)，当前线程是主线程(0x100fa30)。

    然后出现了这样的错误。

    这种情况和上面的错误情况类似。

    关键：

    主线程中的对象m

    子线程的对象n

    m不可以是n的parent

    n不可以是m的parent

    另一种思路：

    再封装一个QObject子类:

    1. #pragma once
    2.  
    3. #include 
    4. #include 
    5. #include 
    6. class socket  : public QObject
    7. {
    8. 	Q_OBJECT
    9.  
    10. public:
    11. 	socket(QObject *parent=nullptr);
    12. 	~socket();
    13. public slots:
    14. 	void connectToHost(QString hostName, quint16 port);
    15. 	void send_msg();
    16. private:
    17. 	QTcpSocket* tcpClient;  //socket
    18. 	QTimer* timer;
    19. 	bool ok;
    20. };
    1. #include "socket.h"
    2. #include 
    3. #include 
    4. socket::socket(QObject *parent)
    5. 	: QObject(parent)
    6. {
    7.     qDebug() << "socket::socket:" << QThread::currentThread();
    8.     timer = new QTimer(this);
    9.     tcpClient = new QTcpSocket(this); //创建socket变量
    10.     connect(timer, &QTimer::timeout, this, [=]() {
    11.         ok = false;
    12.         });
    13.     timer->start(10000);
    14. }
    15.  
    16. socket::~socket()
    17. {
    18. }
    19. void socket::connectToHost(QString addr, quint16 port)
    20. {
    21.     qDebug() << "socket::connectToHost:" << QThread::currentThread();
    22.     tcpClient->connectToHost(addr, port);
    23. }
    24. void socket::send_msg()
    25. {
    26.     qDebug() <<"socket::send_msg():" << QThread::currentThread();
    27.     while (1)
    28.     {
    29.         QString msg = QString::number(1);
    30.         if (ok == false) {
    31.             qDebug() << "[out] " + msg;
    32.             ok = true;
    33.         }
    34.         QByteArray  str = msg.toUtf8();
    35.         str.append('\n');
    36.         tcpClient->write(str);
    37.     }
    38. }
    1. void workThread::run()
    2. {
    3.     qDebug() <<"run():" << QThread::currentThread();
    4.     tcp_client = new socket;
    5.     MainWindow* window = (MainWindow*)(parent());
    6.     connect(window, &MainWindow::connectToHost, tcp_client, &socket::connectToHost);
    7.     qDebug() << "......";
    8.  
    9. }

    这样写的话，不会出现前面的问题。

    但出现了新问题，window发送了connectToHost，而tcp_client没有执行connectToHost。

    因为子线程没有开启事件循环。

    【QT】跨线程的信号槽（connect函数）_qt跨线程信号槽-CSDN博客

    QThread::exec();

    1. void workThread::run()
    2. {
    3.     qDebug() <<"run():" << QThread::currentThread();
    4.     tcp_client = new socket;
    5.     MainWindow* window = (MainWindow*)(parent());
    6.     connect(window, &MainWindow::connectToHost, tcp_client, &socket::connectToHost);
    7.     qDebug() << "......";
    8.  
    9.     QThread::exec();
    10. }

    此时主线程就可以跨线程向子线程通过信号槽发送信息啦。

    思考：

    connect(window, &MainWindow::connectToHost, tcp_client, &socket::connectToHost);

    connectToHost槽函数在哪个线程执行，取决于tcp_client对象在哪个线程。

    客户端：

    多线程版本

    在子线程中：每1ms向服务器发送一次数据。

    （还有很多bug)

    （绑定的资源文件对应这个版本）

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  • 原文地址：https://blog.csdn.net/weixin_51883798/article/details/138156671