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Newbie Question, Working with multiple CPP files and Headers

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  • S Stevendragoes

    @jsulm Do you have a simple example how I can connect two objects together or pass in data members such as QString or QNumber between those two objects?

    jsulmJ Offline
    jsulmJ Offline
    jsulm
    Lifetime Qt Champion
    wrote on last edited by
    #4

    @Stevendragoes Please check the link I provided - there are simple examples.

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

    1 Reply Last reply
    1
    • S Offline
      S Offline
      Stevendragoes
      wrote on last edited by
      #5

      Hello @jsulm As you remember I did a illegal method of Passing in parent into the child to access and play. you have recommended me to have initialise the Timer in another class. However, Now I want to bind the Play, Pause and Stop button. would it be possible because I initialised my timer in another class?

      jsulmJ 1 Reply Last reply
      0
      • S Stevendragoes

        Hello @jsulm As you remember I did a illegal method of Passing in parent into the child to access and play. you have recommended me to have initialise the Timer in another class. However, Now I want to bind the Play, Pause and Stop button. would it be possible because I initialised my timer in another class?

        jsulmJ Offline
        jsulmJ Offline
        jsulm
        Lifetime Qt Champion
        wrote on last edited by
        #6

        @Stevendragoes said in Newbie Question, Working with multiple CPP files and Headers:

        Now I want to bind the Play, Pause and Stop button. would it be possible because I initialised my timer in another class?

        Yes, in your main window add play(), pause() and stop() signals. When you create the child class instance connect these signals to slots in that child class.

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

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        0
        • S Offline
          S Offline
          Stevendragoes
          wrote on last edited by
          #7
          conlinecam* cam = new conlinecam();
          connect(cam, SIGNAL(update()), this, SLOT(update_screen()));
          

          I have this.

          update() is from another cpp file which initialise the Timer and sends the update signal to my update_screen slot.
          So, I have already created QToolButton "Stop" what can I do to Stop the Frames? Is there a specific "Disconnect a Slot" function?

          jsulmJ 1 Reply Last reply
          0
          • S Stevendragoes
            conlinecam* cam = new conlinecam();
            connect(cam, SIGNAL(update()), this, SLOT(update_screen()));
            

            I have this.

            update() is from another cpp file which initialise the Timer and sends the update signal to my update_screen slot.
            So, I have already created QToolButton "Stop" what can I do to Stop the Frames? Is there a specific "Disconnect a Slot" function?

            jsulmJ Offline
            jsulmJ Offline
            jsulm
            Lifetime Qt Champion
            wrote on last edited by
            #8

            @Stevendragoes said in Newbie Question, Working with multiple CPP files and Headers:

            Is there a specific "Disconnect a Slot" function?

            Yes, but there is no need for that in your case. Just stop the timer.

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

            1 Reply Last reply
            0
            • S Offline
              S Offline
              Stevendragoes
              wrote on last edited by Stevendragoes
              #9

              Okay I think I get it. I need to initialise

              conlinecam* cam = new conlinecam();
              

              in my Main Code when I initialise the UI.

              And I have to make my timer public already because I am initialising the timer when I press a Button to get the WebCam Feed

              EDIT: I get then error about __inline because I initialise in the header file

              jsulmJ 1 Reply Last reply
              0
              • S Offline
                S Offline
                Stevendragoes
                wrote on last edited by
                #10

                Then I have a question. why would they say _inline?
                Because I tried to initialise the Timer QObject in the Header FIle. But It simply doesn't allow me @jsulm

                1 Reply Last reply
                0
                • S Stevendragoes

                  Okay I think I get it. I need to initialise

                  conlinecam* cam = new conlinecam();
                  

                  in my Main Code when I initialise the UI.

                  And I have to make my timer public already because I am initialising the timer when I press a Button to get the WebCam Feed

                  EDIT: I get then error about __inline because I initialise in the header file

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

                  @Stevendragoes said in Newbie Question, Working with multiple CPP files and Headers:

                  And I have to make my timer public

                  NO!
                  Why do you think so?
                  The timer is private implementation detail in conlinecam, the outside world does not have to know it even exists.
                  Initialise the timer inside conlinecam.

                  "why would they say _inline?" who?
                  "Because I tried to initialise the Timer QObject in the Header FIle. But It simply doesn't allow me" - please show your code.
                  It is actually as simple as

                  class conlinecam
                  {
                  private:
                      QTimer timer;
                  }
                  

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

                  1 Reply Last reply
                  1
                  • S Offline
                    S Offline
                    Stevendragoes
                    wrote on last edited by
                    #12

                    To simplify the situation, @jsulm I have the following files
                    483bb332-8bca-404a-b603-7d0aa9737752-image.png

                    conlinecam.h has the following code

                    #ifndef CONLINECAM_H
                    #define CONLINECAM_H
                    
                    #include <mainwindow.h>
                    #include <QMainWindow>
                    
                    class conlinecam : public QObject
                    {
                        Q_OBJECT
                    public:
                        conlinecam();
                        ~conlinecam();
                    private:
                        QTimer* camtimer;
                        
                    signals:
                        void update();
                    };
                    
                    #endif // CONLINECAM_H
                    
                    

                    conlinecam.cpp has the following code

                    #include "conlinecam.h"
                    #include "ui_mainwindow.h"
                    #include "mainwindow.h"
                    
                    conlinecam::conlinecam() : QObject()
                    {
                         camtimer = new QTimer(this);
                         connect(camtimer,SIGNAL(timeout()),this,SIGNAL(update()));
                         camtimer->start(100);
                    }
                    
                    conlinecam::~conlinecam()
                    {
                        camtimer->stop();
                    }
                    
                    

                    in my mainwindow.cpp , I have the following code to connect to the conlinecam

                    void MainWindow::on_online_clicked()
                    {
                        conlinecam* cam = new conlinecam();
                        connect(cam, SIGNAL(update()), this, SLOT(update_screen()));
                        onlinecam.open(0);                                 //------------------------CAMERA INPUT---------------------------------//
                        int framewidth = onlinecam.get(cv::CAP_PROP_FRAME_WIDTH);
                        int frameheight = onlinecam.get(cv::CAP_PROP_FRAME_HEIGHT);
                        QString fwidth= QString::number(framewidth);
                        QString fheight = QString::number(frameheight);
                        ui->textEdit->append(fwidth);
                        ui->textEdit->append(fheight);
                    }
                    

                    Now I just want to include Pause and STOP button to pause and stop the timer. But can't because of the following.

                    1. Timer is private in conlinecam.cpp
                    2. conlinecam is only initialised when I pressed the Online PushButton.
                      Hence, I cannot access it's data members
                    jsulmJ 2 Replies Last reply
                    0
                    • S Stevendragoes

                      To simplify the situation, @jsulm I have the following files
                      483bb332-8bca-404a-b603-7d0aa9737752-image.png

                      conlinecam.h has the following code

                      #ifndef CONLINECAM_H
                      #define CONLINECAM_H
                      
                      #include <mainwindow.h>
                      #include <QMainWindow>
                      
                      class conlinecam : public QObject
                      {
                          Q_OBJECT
                      public:
                          conlinecam();
                          ~conlinecam();
                      private:
                          QTimer* camtimer;
                          
                      signals:
                          void update();
                      };
                      
                      #endif // CONLINECAM_H
                      
                      

                      conlinecam.cpp has the following code

                      #include "conlinecam.h"
                      #include "ui_mainwindow.h"
                      #include "mainwindow.h"
                      
                      conlinecam::conlinecam() : QObject()
                      {
                           camtimer = new QTimer(this);
                           connect(camtimer,SIGNAL(timeout()),this,SIGNAL(update()));
                           camtimer->start(100);
                      }
                      
                      conlinecam::~conlinecam()
                      {
                          camtimer->stop();
                      }
                      
                      

                      in my mainwindow.cpp , I have the following code to connect to the conlinecam

                      void MainWindow::on_online_clicked()
                      {
                          conlinecam* cam = new conlinecam();
                          connect(cam, SIGNAL(update()), this, SLOT(update_screen()));
                          onlinecam.open(0);                                 //------------------------CAMERA INPUT---------------------------------//
                          int framewidth = onlinecam.get(cv::CAP_PROP_FRAME_WIDTH);
                          int frameheight = onlinecam.get(cv::CAP_PROP_FRAME_HEIGHT);
                          QString fwidth= QString::number(framewidth);
                          QString fheight = QString::number(frameheight);
                          ui->textEdit->append(fwidth);
                          ui->textEdit->append(fheight);
                      }
                      

                      Now I just want to include Pause and STOP button to pause and stop the timer. But can't because of the following.

                      1. Timer is private in conlinecam.cpp
                      2. conlinecam is only initialised when I pressed the Online PushButton.
                        Hence, I cannot access it's data members
                      jsulmJ Offline
                      jsulmJ Offline
                      jsulm
                      Lifetime Qt Champion
                      wrote on last edited by
                      #13

                      @Stevendragoes

                      1. As I said add slots to conlinecam where you have full access to the timer
                      2. You don't have to access its members - this is whole point of encapsulation.
                      class conlinecam
                      {
                      public slots:
                          void start();
                          void stop();
                          void pause();
                      private:
                          QTimer timer;
                      }
                      

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

                      1 Reply Last reply
                      0
                      • S Stevendragoes

                        To simplify the situation, @jsulm I have the following files
                        483bb332-8bca-404a-b603-7d0aa9737752-image.png

                        conlinecam.h has the following code

                        #ifndef CONLINECAM_H
                        #define CONLINECAM_H
                        
                        #include <mainwindow.h>
                        #include <QMainWindow>
                        
                        class conlinecam : public QObject
                        {
                            Q_OBJECT
                        public:
                            conlinecam();
                            ~conlinecam();
                        private:
                            QTimer* camtimer;
                            
                        signals:
                            void update();
                        };
                        
                        #endif // CONLINECAM_H
                        
                        

                        conlinecam.cpp has the following code

                        #include "conlinecam.h"
                        #include "ui_mainwindow.h"
                        #include "mainwindow.h"
                        
                        conlinecam::conlinecam() : QObject()
                        {
                             camtimer = new QTimer(this);
                             connect(camtimer,SIGNAL(timeout()),this,SIGNAL(update()));
                             camtimer->start(100);
                        }
                        
                        conlinecam::~conlinecam()
                        {
                            camtimer->stop();
                        }
                        
                        

                        in my mainwindow.cpp , I have the following code to connect to the conlinecam

                        void MainWindow::on_online_clicked()
                        {
                            conlinecam* cam = new conlinecam();
                            connect(cam, SIGNAL(update()), this, SLOT(update_screen()));
                            onlinecam.open(0);                                 //------------------------CAMERA INPUT---------------------------------//
                            int framewidth = onlinecam.get(cv::CAP_PROP_FRAME_WIDTH);
                            int frameheight = onlinecam.get(cv::CAP_PROP_FRAME_HEIGHT);
                            QString fwidth= QString::number(framewidth);
                            QString fheight = QString::number(frameheight);
                            ui->textEdit->append(fwidth);
                            ui->textEdit->append(fheight);
                        }
                        

                        Now I just want to include Pause and STOP button to pause and stop the timer. But can't because of the following.

                        1. Timer is private in conlinecam.cpp
                        2. conlinecam is only initialised when I pressed the Online PushButton.
                          Hence, I cannot access it's data members
                        jsulmJ Offline
                        jsulmJ Offline
                        jsulm
                        Lifetime Qt Champion
                        wrote on last edited by
                        #14

                        @Stevendragoes One correction to one of my previous posts: "Yes, in your main window add play(), pause() and stop() signals. When you create the child class instance connect these signals to slots in that child class." - there is no need for to define these signals in main window, just connect the clicked() signals from the buttons to the slots in conlinecam.

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

                        S 1 Reply Last reply
                        0
                        • jsulmJ jsulm

                          @Stevendragoes One correction to one of my previous posts: "Yes, in your main window add play(), pause() and stop() signals. When you create the child class instance connect these signals to slots in that child class." - there is no need for to define these signals in main window, just connect the clicked() signals from the buttons to the slots in conlinecam.

                          S Offline
                          S Offline
                          Stevendragoes
                          wrote on last edited by
                          #15

                          @jsulm said in Newbie Question, Working with multiple CPP files and Headers:

                          just connect the clicked() signals from the buttons to the slots in conlinecam.

                          May I know exactly how? Because I have created the slots. The Signals, Comes from the ToolButtons I have created in my UI form. Do you mean via the Signal/Slot Editor in the UI?

                          jsulmJ 1 Reply Last reply
                          0
                          • S Stevendragoes

                            @jsulm said in Newbie Question, Working with multiple CPP files and Headers:

                            just connect the clicked() signals from the buttons to the slots in conlinecam.

                            May I know exactly how? Because I have created the slots. The Signals, Comes from the ToolButtons I have created in my UI form. Do you mean via the Signal/Slot Editor in the UI?

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

                            @Stevendragoes

                            connect(ui->some_tool_button, SIGNAL(clicked()), conlinecamInstance, SLOT(start()));
                            

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

                            1 Reply Last reply
                            3
                            • S Offline
                              S Offline
                              Stevendragoes
                              wrote on last edited by
                              #17

                              @jsulm
                              Wow. you are amazing. Or maybe I am too inexperienced 4 months into coding..

                              jsulmJ 1 Reply Last reply
                              1
                              • S Stevendragoes

                                @jsulm
                                Wow. you are amazing. Or maybe I am too inexperienced 4 months into coding..

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

                                @Stevendragoes No problem. It takes some time to learn new concepts. Keep learning :-)

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

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                                2
                                • S Offline
                                  S Offline
                                  Stevendragoes
                                  wrote on last edited by
                                  #19

                                  @jsulm Just a question Do you experienced guys have like Discord Chat Groups with the moderators and professionals?

                                  jsulmJ 1 Reply Last reply
                                  0
                                  • S Stevendragoes

                                    @jsulm Just a question Do you experienced guys have like Discord Chat Groups with the moderators and professionals?

                                    jsulmJ Offline
                                    jsulmJ Offline
                                    jsulm
                                    Lifetime Qt Champion
                                    wrote on last edited by
                                    #20

                                    @Stevendragoes You can chat here.
                                    For professional support from Qt Company you will need a commercial license.

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

                                    1 Reply Last reply
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