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Bind Timer with a bool variable.

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  • T Offline
    T Offline
    thomasGl
    wrote on last edited by
    #8

    Ok, thx i forgot to include <QDebug>

    1 Reply Last reply
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    • T Offline
      T Offline
      thomasGl
      wrote on last edited by
      #9

      Hey Guys. Now i am trying to hide my label when my counter ist 5. My counter increases when i click the Button. I made a function where "this->hide(); <----"this" is my label. I am calling that function inside onother function in my Buttonclass, but the program crashes.

      QObject::connect(this,SIGNAL(clicked(bool)),this,SLOT(ButtonclickedXtimes()));  //i am connecting the Button with the function for counting
      
      void Button::ButtonclickedXtimes()   //slot function 
      {
          Label* l;
      
         count++;
         qDebug()<<count;
      
         if(count==5)
         {
             l->labelhide();   //here i am calling the function for the label to hide.
         }
      
      
      }
      /*****************Label Class********************/
      
      Label::Label(QWidget *parent):QLabel(parent)
      {
          this->setGeometry(200,200,200,200);       
          this->setText("Hello World");        //i want that text to hide when counter is 5
      
          
       void Label::labelhide()    //thats my label hide function
      {
          this->hide();
      }
      
      
      Christian EhrlicherC 1 Reply Last reply
      0
      • T thomasGl

        Hey Guys. Now i am trying to hide my label when my counter ist 5. My counter increases when i click the Button. I made a function where "this->hide(); <----"this" is my label. I am calling that function inside onother function in my Buttonclass, but the program crashes.

        QObject::connect(this,SIGNAL(clicked(bool)),this,SLOT(ButtonclickedXtimes()));  //i am connecting the Button with the function for counting
        
        void Button::ButtonclickedXtimes()   //slot function 
        {
            Label* l;
        
           count++;
           qDebug()<<count;
        
           if(count==5)
           {
               l->labelhide();   //here i am calling the function for the label to hide.
           }
        
        
        }
        /*****************Label Class********************/
        
        Label::Label(QWidget *parent):QLabel(parent)
        {
            this->setGeometry(200,200,200,200);       
            this->setText("Hello World");        //i want that text to hide when counter is 5
        
            
         void Label::labelhide()    //thats my label hide function
        {
            this->hide();
        }
        
        
        Christian EhrlicherC Offline
        Christian EhrlicherC Offline
        Christian Ehrlicher
        Lifetime Qt Champion
        wrote on last edited by
        #10

        @thomasGl said in Bind Timer with a bool variable.:

        but the program crashes.

            Label* l;
        
           count++;
           qDebug()<<count;
        
           if(count==5)
           {
               l->labelhide(); 
        

        I would be surprised if it would not crash.
        The same as in your first post - you're using an unitialized pointer so what do you expect?

        Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
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        • T Offline
          T Offline
          thomasGl
          wrote on last edited by
          #11

          i initialized it with NULL , it crashes after 5 .

          Christian EhrlicherC 1 Reply Last reply
          0
          • T thomasGl

            i initialized it with NULL , it crashes after 5 .

            Christian EhrlicherC Offline
            Christian EhrlicherC Offline
            Christian Ehrlicher
            Lifetime Qt Champion
            wrote on last edited by
            #12

            @thomasGl said in Bind Timer with a bool variable.:

            i initialized it with NULL , it crashes after 5 .

            Are you kidding me?
            It must be a valid pointer to your label you want to show or hide...

            Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
            Visit the Qt Academy at https://academy.qt.io/catalog

            JonBJ 1 Reply Last reply
            2
            • Christian EhrlicherC Christian Ehrlicher

              @thomasGl said in Bind Timer with a bool variable.:

              i initialized it with NULL , it crashes after 5 .

              Are you kidding me?
              It must be a valid pointer to your label you want to show or hide...

              JonBJ Offline
              JonBJ Offline
              JonB
              wrote on last edited by
              #13

              @Christian-Ehrlicher Listen, at least it is initialized... ;-)

              1 Reply Last reply
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              • T Offline
                T Offline
                thomasGl
                wrote on last edited by
                #14

                @JonB said in Bind Timer with a bool variable.:

                ;-)

                xD i got this thx guys.

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                • T Offline
                  T Offline
                  thomasGl
                  wrote on last edited by
                  #15

                  Hi, how do i connect that button to the slots onclicked();?

                  #include "twindow.h"
                  #include <QApplication>
                  
                  int main(int argc, char *argv[])
                  {
                      QApplication a(argc, argv);
                  
                      QMainWindow* wind = new QMainWindow();
                      wind->resize(500,500);
                  
                  
                      tWindow*z=new tWindow;
                  
                      //create Button
                      QPushButton* butt = new QPushButton(wind);  
                      butt->setText("click");
                  
                  
                      QLabel* labb = new QLabel(wind);
                      labb->setText("hello World");
                      labb->setGeometry(200,200,200,200);
                  
                      //QObject::connect(button,SIGNAL(clicked(bool)),&a,SLOT(quit()));
                  
                      QObject::connect(butt,SIGNAL(clicked(bool)),tWindow,SLOT(onClicked())); //<-----this 
                  
                  
                  
                  #include "twindow.h"
                  
                  tWindow::tWindow(QWidget *parent):QMainWindow(parent)
                  {
                  
                  
                  }
                  
                  tWindow::~tWindow()
                  {
                  
                  }
                  
                  void tWindow::onClicked()    //<----to this slot.
                  {
                      qDebug()<<"HELLO";
                  }
                  
                  
                  
                  
                  
                  
                  jsulmJ JonBJ 2 Replies Last reply
                  0
                  • T thomasGl

                    Hi, how do i connect that button to the slots onclicked();?

                    #include "twindow.h"
                    #include <QApplication>
                    
                    int main(int argc, char *argv[])
                    {
                        QApplication a(argc, argv);
                    
                        QMainWindow* wind = new QMainWindow();
                        wind->resize(500,500);
                    
                    
                        tWindow*z=new tWindow;
                    
                        //create Button
                        QPushButton* butt = new QPushButton(wind);  
                        butt->setText("click");
                    
                    
                        QLabel* labb = new QLabel(wind);
                        labb->setText("hello World");
                        labb->setGeometry(200,200,200,200);
                    
                        //QObject::connect(button,SIGNAL(clicked(bool)),&a,SLOT(quit()));
                    
                        QObject::connect(butt,SIGNAL(clicked(bool)),tWindow,SLOT(onClicked())); //<-----this 
                    
                    
                    
                    #include "twindow.h"
                    
                    tWindow::tWindow(QWidget *parent):QMainWindow(parent)
                    {
                    
                    
                    }
                    
                    tWindow::~tWindow()
                    {
                    
                    }
                    
                    void tWindow::onClicked()    //<----to this slot.
                    {
                        qDebug()<<"HELLO";
                    }
                    
                    
                    
                    
                    
                    
                    jsulmJ Offline
                    jsulmJ Offline
                    jsulm
                    Lifetime Qt Champion
                    wrote on last edited by
                    #16

                    @thomasGl

                    connect(butt, &QPushButton::clicked, z, &tWindow::onClicked);
                    

                    Please read https://doc.qt.io/qt-6/signalsandslots.html

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

                    1 Reply Last reply
                    1
                    • T thomasGl

                      Hi, how do i connect that button to the slots onclicked();?

                      #include "twindow.h"
                      #include <QApplication>
                      
                      int main(int argc, char *argv[])
                      {
                          QApplication a(argc, argv);
                      
                          QMainWindow* wind = new QMainWindow();
                          wind->resize(500,500);
                      
                      
                          tWindow*z=new tWindow;
                      
                          //create Button
                          QPushButton* butt = new QPushButton(wind);  
                          butt->setText("click");
                      
                      
                          QLabel* labb = new QLabel(wind);
                          labb->setText("hello World");
                          labb->setGeometry(200,200,200,200);
                      
                          //QObject::connect(button,SIGNAL(clicked(bool)),&a,SLOT(quit()));
                      
                          QObject::connect(butt,SIGNAL(clicked(bool)),tWindow,SLOT(onClicked())); //<-----this 
                      
                      
                      
                      #include "twindow.h"
                      
                      tWindow::tWindow(QWidget *parent):QMainWindow(parent)
                      {
                      
                      
                      }
                      
                      tWindow::~tWindow()
                      {
                      
                      }
                      
                      void tWindow::onClicked()    //<----to this slot.
                      {
                          qDebug()<<"HELLO";
                      }
                      
                      
                      
                      
                      
                      
                      JonBJ Offline
                      JonBJ Offline
                      JonB
                      wrote on last edited by JonB
                      #17

                      @thomasGl said in Bind Timer with a bool variable.:

                      QObject::connect(butt,SIGNAL(clicked(bool)),tWindow,SLOT(onClicked())); //<-----this

                      Please do yourself a favor and only use New Signal Slot Syntax. "Old style" with SIGNAL/SLOT() macros is like a decade out of date nowadays!

                      QObject::connect(butt, &QPushButton::clicked, tWindow, &tWindow::onClicked);
                      

                      It is then optional whether you make your tWindow::onClicked() method take the bool parameter --- if you don't care about the "checked" state you don't have to bother. A slot may have fewer parameters than the signal, but never more.

                      Having said this: your error is that tWindow is your class (shame you start it with a lowercase letter, very confusing), your instance is z so you will actually want

                      QObject::connect(butt, &QPushButton::clicked, z, &tWindow::onClicked);
                      
                      T 1 Reply Last reply
                      1
                      • JonBJ JonB

                        @thomasGl said in Bind Timer with a bool variable.:

                        QObject::connect(butt,SIGNAL(clicked(bool)),tWindow,SLOT(onClicked())); //<-----this

                        Please do yourself a favor and only use New Signal Slot Syntax. "Old style" with SIGNAL/SLOT() macros is like a decade out of date nowadays!

                        QObject::connect(butt, &QPushButton::clicked, tWindow, &tWindow::onClicked);
                        

                        It is then optional whether you make your tWindow::onClicked() method take the bool parameter --- if you don't care about the "checked" state you don't have to bother. A slot may have fewer parameters than the signal, but never more.

                        Having said this: your error is that tWindow is your class (shame you start it with a lowercase letter, very confusing), your instance is z so you will actually want

                        QObject::connect(butt, &QPushButton::clicked, z, &tWindow::onClicked);
                        
                        T Offline
                        T Offline
                        thomasGl
                        wrote on last edited by
                        #18

                        i understand thx.

                        1 Reply Last reply
                        0
                        • T Offline
                          T Offline
                          thomasGl
                          wrote on last edited by
                          #19

                          Because of Q_Object i am getting an error: undefined reference to vtable for lablos and error: Id returned 1 exit status. How can i fix that. I need Q_Object.

                          #ifndef LABLOS_H
                          #define LABLOS_H
                          
                          #include <QLabel>
                          
                          class lablos:public QLabel
                          {
                              Q_OBJECT      //<----because of Q_Object i am getting an error..
                          
                          
                          public:
                              lablos(QWidget* parent);
                          
                          
                          };
                          
                          #endif // LABLOS_H
                          
                          
                          Pl45m4P 1 Reply Last reply
                          0
                          • T thomasGl

                            Because of Q_Object i am getting an error: undefined reference to vtable for lablos and error: Id returned 1 exit status. How can i fix that. I need Q_Object.

                            #ifndef LABLOS_H
                            #define LABLOS_H
                            
                            #include <QLabel>
                            
                            class lablos:public QLabel
                            {
                                Q_OBJECT      //<----because of Q_Object i am getting an error..
                            
                            
                            public:
                                lablos(QWidget* parent);
                            
                            
                            };
                            
                            #endif // LABLOS_H
                            
                            
                            Pl45m4P Offline
                            Pl45m4P Offline
                            Pl45m4
                            wrote on last edited by Pl45m4
                            #20

                            @thomasGl

                            Re-run qmake / cmake after you added the Q_OBJECT macro


                            If debugging is the process of removing software bugs, then programming must be the process of putting them in.

                            ~E. W. Dijkstra

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                            2
                            • T Offline
                              T Offline
                              thomasGl
                              wrote on last edited by
                              #21

                              @Pl45m4 qmake / cmake? what do u mean?

                              Pl45m4P 1 Reply Last reply
                              0
                              • T thomasGl

                                @Pl45m4 qmake / cmake? what do u mean?

                                Pl45m4P Offline
                                Pl45m4P Offline
                                Pl45m4
                                wrote on last edited by
                                #22

                                @thomasGl

                                You are using probably one of them. It's the build tool that "Makes" your code and builds your app / executable from your source code.

                                Especially when you add the QObject macro to some classes, you have to re-run it, to ensure that everything is updated. Sometimes your IDE (like QtCreator) notices, sometimes it doesn't.


                                If debugging is the process of removing software bugs, then programming must be the process of putting them in.

                                ~E. W. Dijkstra

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                                • T Offline
                                  T Offline
                                  thomasGl
                                  wrote on last edited by
                                  #23

                                  Thank you it works.

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                                  • T Offline
                                    T Offline
                                    thomasGl
                                    wrote on last edited by
                                    #24

                                    Hi, i stuck again. I am trying to show my label after 5 clicks on my Pushbutton else label should hide. How can i count 1 click after 1 click? My problem is the loop i have only managed to get 5 counts with no click. I need 1 count with 1 click on the button. I tried to put QObject::connect(but, &Button::clicked, but,&Button::count); in my loop instead of "but->count" but it does not work. Do i need a mousepressevent here?

                                    void Button::count()              //thats my method i have connected with my Button
                                    {
                                        counter++;
                                         qDebug()<<counter;
                                    }
                                    
                                    
                                    
                                    QObject::connect(but, &Button::clicked, but,&Button::count);    //Connection
                                    
                                    
                                    
                                        while (but->counter!=5)   //my loop
                                        {
                                            if(but->counter==5)
                                            {
                                                labb->show();
                                            }
                                            else
                                            {
                                               but->count();    //here i want to click and count
                                            }
                                        }
                                    
                                    
                                    
                                    
                                    Pl45m4P 1 Reply Last reply
                                    0
                                    • T thomasGl

                                      Hi, i stuck again. I am trying to show my label after 5 clicks on my Pushbutton else label should hide. How can i count 1 click after 1 click? My problem is the loop i have only managed to get 5 counts with no click. I need 1 count with 1 click on the button. I tried to put QObject::connect(but, &Button::clicked, but,&Button::count); in my loop instead of "but->count" but it does not work. Do i need a mousepressevent here?

                                      void Button::count()              //thats my method i have connected with my Button
                                      {
                                          counter++;
                                           qDebug()<<counter;
                                      }
                                      
                                      
                                      
                                      QObject::connect(but, &Button::clicked, but,&Button::count);    //Connection
                                      
                                      
                                      
                                          while (but->counter!=5)   //my loop
                                          {
                                              if(but->counter==5)
                                              {
                                                  labb->show();
                                              }
                                              else
                                              {
                                                 but->count();    //here i want to click and count
                                              }
                                          }
                                      
                                      
                                      
                                      
                                      Pl45m4P Offline
                                      Pl45m4P Offline
                                      Pl45m4
                                      wrote on last edited by
                                      #25

                                      @thomasGl

                                      The while loop blocks your counting on click. You dont need it.

                                      Add something like

                                      QObject::connect(but, &Button::clicked, this ,&MainWindow::onCount);
                                      
                                      
                                      MainWindow::onCount{
                                      if(but->counter==5)
                                              {
                                                  labb->show();
                                              }
                                      
                                      }
                                      

                                      If debugging is the process of removing software bugs, then programming must be the process of putting them in.

                                      ~E. W. Dijkstra

                                      1 Reply Last reply
                                      2
                                      • T Offline
                                        T Offline
                                        thomasGl
                                        wrote on last edited by
                                        #26

                                        Hey. I how can i make that label to show my counter?

                                        void mainWin::onCount()
                                        {
                                            if(counter==4)
                                            {
                                                labb->show();
                                                labb->setText("Hello World");
                                            }
                                        
                                        
                                            counter++;
                                            
                                            qDebug()<<counter;    //i want that counter to be shown with that label2
                                            
                                            label2->setText(counter);  //i want that label to show my  counter
                                        
                                        
                                        
                                        }
                                        
                                        jsulmJ JonBJ 2 Replies Last reply
                                        0
                                        • T thomasGl

                                          Hey. I how can i make that label to show my counter?

                                          void mainWin::onCount()
                                          {
                                              if(counter==4)
                                              {
                                                  labb->show();
                                                  labb->setText("Hello World");
                                              }
                                          
                                          
                                              counter++;
                                              
                                              qDebug()<<counter;    //i want that counter to be shown with that label2
                                              
                                              label2->setText(counter);  //i want that label to show my  counter
                                          
                                          
                                          
                                          }
                                          
                                          jsulmJ Offline
                                          jsulmJ Offline
                                          jsulm
                                          Lifetime Qt Champion
                                          wrote on last edited by
                                          #27

                                          @thomasGl said in Bind Timer with a bool variable.:

                                          //i want that label to show my counter

                                          Then convert it to a string first using https://doc.qt.io/qt-6/qstring.html#number ...

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

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