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Set Delay Timer

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  • Y Offline
    Y Offline
    Yrandom
    wrote on last edited by Yrandom
    #1

    Hi
    I make a Programm using C++ and Netbeans with a lot of pushbutton

    I would like to do something like this
    When i click the button, it should change to the Position i want and Change the border style or maybe Background to red or whatever and after maybe 300ms it should Change back to normal
    The part with changing Position worked for me.

    I used to Google but I didn found any solution. I try something like this but itsnot work

    void Game::buttonClicked(QWidget* _button){
    // Clicked button identifire with QSignalMapper
        QPushButton* b = dynamic_cast<QPushButton*>(_button);           //cast widget to pushbutton
        int index = layout->indexOf(_button);                           // find out the index of button in gridlayout
        int row, col,ax,bx;
        if(index != -1){                                
        layout->getItemPosition(index,&row,&col,&ax,&bx);               // get the koordinate of this item
        }
        
              // Set border color
            //b->setStyleSheet("border:2px solid #ff0000"); or set Background color
            b->setStyleSheet("background-color:green");
    
    //make delay time here to Show this Color for only a specific amoun of time like Sleep(MS) in Windows.h
    // TODO
    //QThread:usleep() seem not work, QTimer i think also dont work
    
                  b->setStyleSheet(""); // set stylesheet back
          
         }
             }
    

    Any Solution for this?

    Thanks

    J.HilkJ 1 Reply Last reply
    0
    • VRoninV Offline
      VRoninV Offline
      VRonin
      wrote on last edited by VRonin
      #2

      You made it way more complicated than necessary. no need to use QSignalMapper either

      connect(button,&QPushButton::clicked,[button]()->void{
      button->setStyleSheet(QStringLiteral"background-color:green"));
      QTimer::singleShot(300,[button]()->void{button->setStyleSheet(QString());});
      });
      

      "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
      ~Napoleon Bonaparte

      On a crusade to banish setIndexWidget() from the holy land of Qt

      1 Reply Last reply
      1
      • Y Offline
        Y Offline
        Yrandom
        wrote on last edited by
        #3
        This post is deleted!
        jsulmJ VRoninV 2 Replies Last reply
        0
        • SGaistS Offline
          SGaistS Offline
          SGaist
          Lifetime Qt Champion
          wrote on last edited by
          #4

          Hi and welcome to devnet,

          Can you post the code that is triggering the error ?

          Interested in AI ? www.idiap.ch
          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

          1 Reply Last reply
          0
          • Y Yrandom

            This post is deleted!

            jsulmJ Offline
            jsulmJ Offline
            jsulm
            Lifetime Qt Champion
            wrote on last edited by
            #5

            @Yrandom said in Set Delay Timer:

            connect(b,&QPushButton::click(),b->void{

            Why did you add () after click?
            The correct name of the slot is http://doc.qt.io/qt-5/qabstractbutton.html#clicked, so it must be:

            connect(b,&QPushButton::clicked,[b]()->void{
            ...
            

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

            1 Reply Last reply
            1
            • Y Yrandom

              Hi
              I make a Programm using C++ and Netbeans with a lot of pushbutton

              I would like to do something like this
              When i click the button, it should change to the Position i want and Change the border style or maybe Background to red or whatever and after maybe 300ms it should Change back to normal
              The part with changing Position worked for me.

              I used to Google but I didn found any solution. I try something like this but itsnot work

              void Game::buttonClicked(QWidget* _button){
              // Clicked button identifire with QSignalMapper
                  QPushButton* b = dynamic_cast<QPushButton*>(_button);           //cast widget to pushbutton
                  int index = layout->indexOf(_button);                           // find out the index of button in gridlayout
                  int row, col,ax,bx;
                  if(index != -1){                                
                  layout->getItemPosition(index,&row,&col,&ax,&bx);               // get the koordinate of this item
                  }
                  
                        // Set border color
                      //b->setStyleSheet("border:2px solid #ff0000"); or set Background color
                      b->setStyleSheet("background-color:green");
              
              //make delay time here to Show this Color for only a specific amoun of time like Sleep(MS) in Windows.h
              // TODO
              //QThread:usleep() seem not work, QTimer i think also dont work
              
                            b->setStyleSheet(""); // set stylesheet back
                    
                   }
                       }
              

              Any Solution for this?

              Thanks

              J.HilkJ Offline
              J.HilkJ Offline
              J.Hilk
              Moderators
              wrote on last edited by
              #6

              @Yrandom You got a lot of good advise from the others. I'll try to add to that.
              If you don't wan't do rewrite your code too much, you can change your fuction to something like this.

              void VerschiebeSpiel::buttonClicked(QWidget* _button){
                  QPushButton* b = dynamic_cast<QPushButton*>(_button);  
                  int index = layout->indexOf(_button);   
                  int row, col,ax,bx;
                  
                  if(index != -1){                                
                      layout->getItemPosition(index,&row,&col,&ax,&bx);
                  }
              
                  if(b){//check if valid cast
                      b->setStyleSheet("background-color:green");
                      //Timer + Lambda-function to reset the button after 1000 msec
                      QTimer::singleShot(1000,this,[=]{b->setStyleSheet("background-color:red");});
                  }
              }       
              

              Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


              Q: What's that?
              A: It's blue light.
              Q: What does it do?
              A: It turns blue.

              Y 1 Reply Last reply
              0
              • SGaistS Offline
                SGaistS Offline
                SGaist
                Lifetime Qt Champion
                wrote on last edited by
                #7

                To both: use qobject_cast when dealing with QObject based classes.

                Interested in AI ? www.idiap.ch
                Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                1 Reply Last reply
                2
                • J.HilkJ J.Hilk

                  @Yrandom You got a lot of good advise from the others. I'll try to add to that.
                  If you don't wan't do rewrite your code too much, you can change your fuction to something like this.

                  void VerschiebeSpiel::buttonClicked(QWidget* _button){
                      QPushButton* b = dynamic_cast<QPushButton*>(_button);  
                      int index = layout->indexOf(_button);   
                      int row, col,ax,bx;
                      
                      if(index != -1){                                
                          layout->getItemPosition(index,&row,&col,&ax,&bx);
                      }
                  
                      if(b){//check if valid cast
                          b->setStyleSheet("background-color:green");
                          //Timer + Lambda-function to reset the button after 1000 msec
                          QTimer::singleShot(1000,this,[=]{b->setStyleSheet("background-color:red");});
                      }
                  }       
                  
                  Y Offline
                  Y Offline
                  Yrandom
                  wrote on last edited by Yrandom
                  #8

                  @J.Hilk

                  thx for this example
                  it works great.

                  also just mention: i found out other solution for that

                  using processevents and currenttime
                  but i want to unterstand how this part work

                  QCoreApplication::processEvents( QEventLoop::AllEvents, 100 );
                  

                  What is the 100(maxtime) mean ? because i just need to process the Event again (Loop all Event) and the current time will increase automatically.
                  I dont need to put 100 as Parameter and it still work

                  Thx all for the answer

                  
                  // Delay time for button color
                  void ss::delay(int millisecondsToWait )
                  {
                      QTime dieTime = QTime::currentTime().addMSecs( millisecondsToWait );
                      while( QTime::currentTime() < dieTime )
                      {
                          QCoreApplication::processEvents( QEventLoop::AllEvents, 100 );
                      }
                  }
                  
                  jsulmJ J.HilkJ 2 Replies Last reply
                  0
                  • Y Yrandom

                    @J.Hilk

                    thx for this example
                    it works great.

                    also just mention: i found out other solution for that

                    using processevents and currenttime
                    but i want to unterstand how this part work

                    QCoreApplication::processEvents( QEventLoop::AllEvents, 100 );
                    

                    What is the 100(maxtime) mean ? because i just need to process the Event again (Loop all Event) and the current time will increase automatically.
                    I dont need to put 100 as Parameter and it still work

                    Thx all for the answer

                    
                    // Delay time for button color
                    void ss::delay(int millisecondsToWait )
                    {
                        QTime dieTime = QTime::currentTime().addMSecs( millisecondsToWait );
                        while( QTime::currentTime() < dieTime )
                        {
                            QCoreApplication::processEvents( QEventLoop::AllEvents, 100 );
                        }
                    }
                    
                    jsulmJ Offline
                    jsulmJ Offline
                    jsulm
                    Lifetime Qt Champion
                    wrote on last edited by jsulm
                    #9

                    @Yrandom said in Set Delay Timer:

                    QCoreApplication::processEvents

                    Check documentation http://doc.qt.io/qt-5/qcoreapplication.html#processEvents-1
                    "Processes pending events for the calling thread for maxtime milliseconds or until there are no more events to process, whichever is shorter."
                    Keep in mind that your solution isn't nice from design point of view and will consume a lot of CPU power.

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

                    1 Reply Last reply
                    1
                    • Y Yrandom

                      This post is deleted!

                      VRoninV Offline
                      VRoninV Offline
                      VRonin
                      wrote on last edited by
                      #10

                      @Yrandom said in Set Delay Timer:

                      VerschiebeSpiel.cpp.cc: In member function 'void erschiebeSpiel::buttonClicked(QWidget*)':

                      That's not where you should put the connect. my code snippet should go just after you create the button (in the constructor?)

                      while( QTime::currentTime() < dieTime )
                      {
                      QCoreApplication::processEvents( QEventLoop::AllEvents, 100 );
                      }

                      This is just bad design. you are blocking the main thread and forcing the event loop to kinda keep the UI responsive. Nasty

                      "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                      ~Napoleon Bonaparte

                      On a crusade to banish setIndexWidget() from the holy land of Qt

                      1 Reply Last reply
                      1
                      • Y Yrandom

                        @J.Hilk

                        thx for this example
                        it works great.

                        also just mention: i found out other solution for that

                        using processevents and currenttime
                        but i want to unterstand how this part work

                        QCoreApplication::processEvents( QEventLoop::AllEvents, 100 );
                        

                        What is the 100(maxtime) mean ? because i just need to process the Event again (Loop all Event) and the current time will increase automatically.
                        I dont need to put 100 as Parameter and it still work

                        Thx all for the answer

                        
                        // Delay time for button color
                        void ss::delay(int millisecondsToWait )
                        {
                            QTime dieTime = QTime::currentTime().addMSecs( millisecondsToWait );
                            while( QTime::currentTime() < dieTime )
                            {
                                QCoreApplication::processEvents( QEventLoop::AllEvents, 100 );
                            }
                        }
                        
                        J.HilkJ Offline
                        J.HilkJ Offline
                        J.Hilk
                        Moderators
                        wrote on last edited by
                        #11

                        @Yrandom

                        Usually during a while loop, all other tasks are suspendet until the loop or more precisely the function returns. That includes the paint/repaint event that is triggered by setStyleSheet().

                        QCoreApplication::processEvents() is an uncomely way to tell your app, "That with the function, do whatever else is qued".
                        The Int value you pass to processEvents is a max value in -I believe -ms, you give other Processes to finish their stuff, after that time your code after the call gets processed again.

                        a While loop now is calling that every eventloop-cycle

                        My advice, don't use it, if you have other options.


                        Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


                        Q: What's that?
                        A: It's blue light.
                        Q: What does it do?
                        A: It turns blue.

                        1 Reply Last reply
                        1
                        • M Offline
                          M Offline
                          mpergand
                          wrote on last edited by
                          #12

                          A wait function like this:

                          void wait(float sec)
                          {
                              QElapsedTimer timer;
                              timer.start();
                          
                              while(! timer.hasExpired(sec*1000))
                                  QCoreApplication::processEvents();
                          }
                          

                          allows you to simpy do that:

                          b->setStyleSheet("background-color:green");
                          wait(0.3);
                          b->setStyleSheet("background-color:red");
                          

                          Pretty and clean isn't it ?

                          J.HilkJ VRoninV 2 Replies Last reply
                          0
                          • M mpergand

                            A wait function like this:

                            void wait(float sec)
                            {
                                QElapsedTimer timer;
                                timer.start();
                            
                                while(! timer.hasExpired(sec*1000))
                                    QCoreApplication::processEvents();
                            }
                            

                            allows you to simpy do that:

                            b->setStyleSheet("background-color:green");
                            wait(0.3);
                            b->setStyleSheet("background-color:red");
                            

                            Pretty and clean isn't it ?

                            J.HilkJ Offline
                            J.HilkJ Offline
                            J.Hilk
                            Moderators
                            wrote on last edited by
                            #13

                            @mpergand said in Set Delay Timer:

                            while(! timer.hasExpired(sec*1000))
                                QCoreApplication::processEvents();
                            

                            Pretty and clean isn't it ?

                            No, it's not!

                            Do not use QCoreApplication::processEvents if you can avoid it!


                            Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


                            Q: What's that?
                            A: It's blue light.
                            Q: What does it do?
                            A: It turns blue.

                            1 Reply Last reply
                            0
                            • M mpergand

                              A wait function like this:

                              void wait(float sec)
                              {
                                  QElapsedTimer timer;
                                  timer.start();
                              
                                  while(! timer.hasExpired(sec*1000))
                                      QCoreApplication::processEvents();
                              }
                              

                              allows you to simpy do that:

                              b->setStyleSheet("background-color:green");
                              wait(0.3);
                              b->setStyleSheet("background-color:red");
                              

                              Pretty and clean isn't it ?

                              VRoninV Offline
                              VRoninV Offline
                              VRonin
                              wrote on last edited by
                              #14

                              @mpergand said in Set Delay Timer:

                              Pretty and clean isn't it ?

                              No it is not. it uses 75% of one of my CPU cores for absolutely nothing

                              "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                              ~Napoleon Bonaparte

                              On a crusade to banish setIndexWidget() from the holy land of Qt

                              M 1 Reply Last reply
                              0
                              • M Offline
                                M Offline
                                mpergand
                                wrote on last edited by mpergand
                                #15

                                @j.hilk Do not use QCoreApplication::processEvents if you can avoid it!

                                Why ?
                                Explain any good reason to avoid it.

                                J.HilkJ 1 Reply Last reply
                                0
                                • M mpergand

                                  @j.hilk Do not use QCoreApplication::processEvents if you can avoid it!

                                  Why ?
                                  Explain any good reason to avoid it.

                                  J.HilkJ Offline
                                  J.HilkJ Offline
                                  J.Hilk
                                  Moderators
                                  wrote on last edited by J.Hilk
                                  #16

                                  @mpergand said in Set Delay Timer:

                                  @j.hilk Do not use QCoreApplication::processEvents if you can avoid it!

                                  Why ?
                                  Explain any good reason to avoid it.

                                  At least used in such a loop->
                                  @VRonin said in Set Delay Timer:

                                  No it is not. it uses 75% of one of my CPU cores for absolutely nothing

                                  Its also contrarian to the event-driven programming approach


                                  Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


                                  Q: What's that?
                                  A: It's blue light.
                                  Q: What does it do?
                                  A: It turns blue.

                                  1 Reply Last reply
                                  0
                                  • VRoninV VRonin

                                    @mpergand said in Set Delay Timer:

                                    Pretty and clean isn't it ?

                                    No it is not. it uses 75% of one of my CPU cores for absolutely nothing

                                    M Offline
                                    M Offline
                                    mpergand
                                    wrote on last edited by
                                    #17

                                    @VRonin said in Set Delay Timer:

                                    No it is not. it uses 75% of one of my CPU cores for absolutely nothing

                                    For .3 sec not a big deal.
                                    I agree, that it's should by used for short period only (< 1 sec)

                                    The main drawback I know (i use the same principle on MacOS) is that it can leading to some reentrant call in some cases.

                                    VRoninV 1 Reply Last reply
                                    0
                                    • M mpergand

                                      @VRonin said in Set Delay Timer:

                                      No it is not. it uses 75% of one of my CPU cores for absolutely nothing

                                      For .3 sec not a big deal.
                                      I agree, that it's should by used for short period only (< 1 sec)

                                      The main drawback I know (i use the same principle on MacOS) is that it can leading to some reentrant call in some cases.

                                      VRoninV Offline
                                      VRoninV Offline
                                      VRonin
                                      wrote on last edited by
                                      #18

                                      @mpergand said in Set Delay Timer:

                                      For .3 sec not a big deal.

                                      It is. especially on mobile/embedded hardware. it's just bad design especially when alternatives based of QEventLoop exist (but of course use the async is ALWAYS the best design)

                                      "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                                      ~Napoleon Bonaparte

                                      On a crusade to banish setIndexWidget() from the holy land of Qt

                                      M 1 Reply Last reply
                                      3
                                      • VRoninV VRonin

                                        @mpergand said in Set Delay Timer:

                                        For .3 sec not a big deal.

                                        It is. especially on mobile/embedded hardware. it's just bad design especially when alternatives based of QEventLoop exist (but of course use the async is ALWAYS the best design)

                                        M Offline
                                        M Offline
                                        mpergand
                                        wrote on last edited by
                                        #19

                                        @VRonin said in Set Delay Timer:

                                        It is. especially on mobile/embedded hardware. it's just bad design especially when alternatives based of QEventLoop exist (but of course use the async is ALWAYS the best design)

                                        Ok, add a small QThread::sleep should do the job as well.

                                        Please, can you post an example of a wait function with a QEventLoop instead.

                                        1 Reply Last reply
                                        0
                                        • VRoninV Offline
                                          VRoninV Offline
                                          VRonin
                                          wrote on last edited by VRonin
                                          #20

                                          add a small QThread::sleep should do the job as well

                                          it does not, reason in link below

                                          can you post an example of a wait function with a QEventLoop instead.

                                          https://forum.qt.io/topic/78715/why-my-timer-is-not-emit-timeout-signal

                                          "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                                          ~Napoleon Bonaparte

                                          On a crusade to banish setIndexWidget() from the holy land of Qt

                                          1 Reply Last reply
                                          0

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