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A UDP socket send/receive.

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  • jsulmJ jsulm

    @jenya7 said in A UDP socket send/receive.:

    How can I pass the data outside the class?

    Using signals and slots. In your MyUDP class add a signal with a QString parameter. Then emit this signal when you want to show a message with the text as signal parameter. Connect this signal with a slot in your GUI class which is responsible for showing the message. In this slot you can show the text then.

    J Offline
    J Offline
    jenya7
    wrote on last edited by jenya7
    #10

    @jsulm said in A UDP socket send/receive.:

    @jenya7 said in A UDP socket send/receive.:

    How can I pass the data outside the class?

    Using signals and slots. In your MyUDP class add a signal with a QString parameter. Then emit this signal when you want to show a message with the text as signal parameter. Connect this signal with a slot in your GUI class which is responsible for showing the message. In this slot you can show the text then.

    Sorry I fail to understand. Right now the receiving is working and I got the message in a global string
    msg = QString(udp_buffer);
    Now what signal do I emit?

    jsulmJ 1 Reply Last reply
    0
    • J jenya7

      @jsulm said in A UDP socket send/receive.:

      @jenya7 said in A UDP socket send/receive.:

      How can I pass the data outside the class?

      Using signals and slots. In your MyUDP class add a signal with a QString parameter. Then emit this signal when you want to show a message with the text as signal parameter. Connect this signal with a slot in your GUI class which is responsible for showing the message. In this slot you can show the text then.

      Sorry I fail to understand. Right now the receiving is working and I got the message in a global string
      msg = QString(udp_buffer);
      Now what signal do I emit?

      jsulmJ Online
      jsulmJ Online
      jsulm
      Lifetime Qt Champion
      wrote on last edited by
      #11

      @jenya7 said in A UDP socket send/receive.:

      Now what signal do I emit?

      One you need to define in your MyUDP class as I wrote before:

      class MyUDP...
      {
      signals:
          void showMessage(const QString& msg);
      ...
      void MyUDP::ReadyRead()
      {
         ...
         showMessage(QString(buffer));
      

      Please read https://doc.qt.io/qt-5/signalsandslots.html

      https://forum.qt.io/topic/113070/qt-code-of-conduct

      J 1 Reply Last reply
      2
      • jsulmJ jsulm

        @jenya7 said in A UDP socket send/receive.:

        Now what signal do I emit?

        One you need to define in your MyUDP class as I wrote before:

        class MyUDP...
        {
        signals:
            void showMessage(const QString& msg);
        ...
        void MyUDP::ReadyRead()
        {
           ...
           showMessage(QString(buffer));
        

        Please read https://doc.qt.io/qt-5/signalsandslots.html

        J Offline
        J Offline
        jenya7
        wrote on last edited by
        #12

        @jsulm
        Wow. That's cool. And I can implement showMessage(const QString& msg); in any file?
        Say ui->textEditNetRX->append(msg); is available in "mainwindow.cpp.

        jsulmJ 1 Reply Last reply
        0
        • J jenya7

          @jsulm
          Wow. That's cool. And I can implement showMessage(const QString& msg); in any file?
          Say ui->textEditNetRX->append(msg); is available in "mainwindow.cpp.

          jsulmJ Online
          jsulmJ Online
          jsulm
          Lifetime Qt Champion
          wrote on last edited by
          #13

          @jenya7 said in A UDP socket send/receive.:

          in any file?

          Yes, just add a slot where you need it and connect it to the signal.
          Signals/slots is a very powerful concept and it also helps to decouple classes from each other. For example your MyUDP class does not need to know who connects to its signal, it just emits the signal. You can connect 0..n slots to a signal, you can connect a signal to 0..n other signals.

          https://forum.qt.io/topic/113070/qt-code-of-conduct

          J 1 Reply Last reply
          2
          • jsulmJ jsulm

            @jenya7 said in A UDP socket send/receive.:

            in any file?

            Yes, just add a slot where you need it and connect it to the signal.
            Signals/slots is a very powerful concept and it also helps to decouple classes from each other. For example your MyUDP class does not need to know who connects to its signal, it just emits the signal. You can connect 0..n slots to a signal, you can connect a signal to 0..n other signals.

            J Offline
            J Offline
            jenya7
            wrote on last edited by
            #14

            @jsulm
            Thank you very much.

            1 Reply Last reply
            0
            • J Offline
              J Offline
              jenya7
              wrote on last edited by
              #15

              In mainwindow.h I created a slot

              class MainWindow : public QMainWindow
              {
                  Q_OBJECT
              
              public:
                  explicit MainWindow(QWidget *parent = nullptr);
                  ~MainWindow();
              
                  MyUDP udp;
              
              public slots:
                  void ShowUdpMessage(const QString& msg, const QByteArray data);
              //and so on...
              

              in mainwindow.cpp

              void MainWindow::ShowUdpMessage(const QString& msg, const QByteArray data)
              {
                  QByteArray arr = data;
                  ui->textEditNetRX->append(msg);
              }
              

              now in main.cpp

              
              MainWindow w;
               w.show();
              
              QObject::connect(&???, &???, &w, &MainWindow::ShowUdpMessage);
              

              How do I tie the signal source?
              The signal generates by MyUDP udp that resides in the MainWindow class.

              jsulmJ 1 Reply Last reply
              0
              • J jenya7

                In mainwindow.h I created a slot

                class MainWindow : public QMainWindow
                {
                    Q_OBJECT
                
                public:
                    explicit MainWindow(QWidget *parent = nullptr);
                    ~MainWindow();
                
                    MyUDP udp;
                
                public slots:
                    void ShowUdpMessage(const QString& msg, const QByteArray data);
                //and so on...
                

                in mainwindow.cpp

                void MainWindow::ShowUdpMessage(const QString& msg, const QByteArray data)
                {
                    QByteArray arr = data;
                    ui->textEditNetRX->append(msg);
                }
                

                now in main.cpp

                
                MainWindow w;
                 w.show();
                
                QObject::connect(&???, &???, &w, &MainWindow::ShowUdpMessage);
                

                How do I tie the signal source?
                The signal generates by MyUDP udp that resides in the MainWindow class.

                jsulmJ Online
                jsulmJ Online
                jsulm
                Lifetime Qt Champion
                wrote on last edited by
                #16

                @jenya7

                QObject::connect(&udp, &MyUDP::showMessage, &w, &MainWindow::ShowUdpMessage);
                

                https://forum.qt.io/topic/113070/qt-code-of-conduct

                J 1 Reply Last reply
                1
                • jsulmJ jsulm

                  @jenya7

                  QObject::connect(&udp, &MyUDP::showMessage, &w, &MainWindow::ShowUdpMessage);
                  
                  J Offline
                  J Offline
                  jenya7
                  wrote on last edited by
                  #17

                  @jsulm
                  QObject::connect(&udp, &MyUDP::showMessage, &w, &MainWindow::ShowUdpMessage);
                  &udp - is not visible in the scope. also MainWindow::udp <- udp not recognized although it declared public:MyUDP udp; in MainWindow.

                  jsulmJ 1 Reply Last reply
                  0
                  • J jenya7

                    @jsulm
                    QObject::connect(&udp, &MyUDP::showMessage, &w, &MainWindow::ShowUdpMessage);
                    &udp - is not visible in the scope. also MainWindow::udp <- udp not recognized although it declared public:MyUDP udp; in MainWindow.

                    jsulmJ Online
                    jsulmJ Online
                    jsulm
                    Lifetime Qt Champion
                    wrote on last edited by jsulm
                    #18

                    @jenya7 You should do the connection inside MainWindow (for example in its constructor), because MainWindow needs the signal and it also has the MyUDP instance...

                    "although it declared public:MyUDP udp" - don't declare it public, just do the connection inside MainWindow.

                    https://forum.qt.io/topic/113070/qt-code-of-conduct

                    1 Reply Last reply
                    1
                    • J Offline
                      J Offline
                      jenya7
                      wrote on last edited by jenya7
                      #19

                      I try in the constructor

                      MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow)
                      {
                          ui->setupUi(this);
                          ui->tabWidget->setCurrentIndex(0);
                          ui->textEditTerminalTx->installEventFilter(this);
                          
                           QObject::connect(&udp, &MyUDP::ShowUdpMessage, &MainWindow, &MainWindow::ShowUdpMessage);
                      }
                      

                      third argument - &MainWindow <- 'MainWindow' does not refer to a value.

                      JonBJ 1 Reply Last reply
                      0
                      • J jenya7

                        I try in the constructor

                        MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow)
                        {
                            ui->setupUi(this);
                            ui->tabWidget->setCurrentIndex(0);
                            ui->textEditTerminalTx->installEventFilter(this);
                            
                             QObject::connect(&udp, &MyUDP::ShowUdpMessage, &MainWindow, &MainWindow::ShowUdpMessage);
                        }
                        

                        third argument - &MainWindow <- 'MainWindow' does not refer to a value.

                        JonBJ Offline
                        JonBJ Offline
                        JonB
                        wrote on last edited by JonB
                        #20

                        @jenya7
                        &MainWindow should be this. And you ought understand why (it's an instance of MainWindow).

                        1 Reply Last reply
                        3
                        • J Offline
                          J Offline
                          jenya7
                          wrote on last edited by
                          #21

                          OMG! It's working! Thank you so much!

                          1 Reply Last reply
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