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signal is not working

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  • F Offline
    F Offline
    frnklu20
    wrote on last edited by
    #8

    but how can i write it in the new sintax?

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    • Christian EhrlicherC Offline
      Christian EhrlicherC Offline
      Christian Ehrlicher
      Lifetime Qt Champion
      wrote on last edited by
      #9

      @frnklu20 said in signal is not working:

      but how can i write it in the new sintax?

      By looking into the documentation

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

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      • F Offline
        F Offline
        frnklu20
        wrote on last edited by frnklu20
        #10
        connect(scene, &DiagramScene::addtreeitem),
                    this, &MainWindow::handleaddtreeitem);
        

        it gives me an error in addtreeitem, it says" error: no matching member function for call to 'connect'"

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        • SGaistS Offline
          SGaistS Offline
          SGaist
          Lifetime Qt Champion
          wrote on last edited by
          #11

          You are missing the & for the function parameters.

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

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          • F Offline
            F Offline
            frnklu20
            wrote on last edited by frnklu20
            #12

            yeah i fixed it! but it gives me an error in the connect

            0_1568918552432_c8677482-2b41-434e-aa09-3928e4e4d1c3-image.png

            if i put the &parameter in the objects it says cannot take the adress of an rvalue of type MainWindow and no matching member function for call to 'connect'

            jsulmJ Pl45m4P 2 Replies Last reply
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            • SGaistS Offline
              SGaistS Offline
              SGaist
              Lifetime Qt Champion
              wrote on last edited by
              #13

              And what error exactly ?

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

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              • F Offline
                F Offline
                frnklu20
                wrote on last edited by
                #14

                in the no matching member it says:
                mainwindow.cpp:25:5: error: no matching member function for call to 'connect'
                qobject.h:228:43: note: candidate function template not viable: requires at least 4 arguments, but 2 were provided
                qobject.h:260:13: note: candidate function template not viable: requires 3 arguments, but 2 were provided
                qobject.h:269:13: note: candidate function template not viable: requires at least 4 arguments, but 2 were provided
                qobject.h:300:13: note: candidate function template not viable: requires 3 arguments, but 2 were provided
                qobject.h:308:13: note: candidate function template not viable: requires at least 4 arguments, but 2 were provided
                qobject.h:463:41: note: candidate function not viable: requires at least 3 arguments, but 2 were provided
                qobject.h:208:36: note: candidate function not viable: requires at least 4 arguments, but 2 were provided
                qobject.h:211:36: note: candidate function not viable: requires at least 4 arguments, but 2 were provided

                don't know what that means

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                • Christian EhrlicherC Offline
                  Christian EhrlicherC Offline
                  Christian Ehrlicher
                  Lifetime Qt Champion
                  wrote on last edited by Christian Ehrlicher
                  #15

                  Since you're doing the connect in a class which is not derived from QObject or in main() you have forgot 'QObject::' before connect since it's a static function of QObject

                  And you've a syntax error in your code - '&DiagramScene::addtreeitem),'

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

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                  • F frnklu20

                    yeah i fixed it! but it gives me an error in the connect

                    0_1568918552432_c8677482-2b41-434e-aa09-3928e4e4d1c3-image.png

                    if i put the &parameter in the objects it says cannot take the adress of an rvalue of type MainWindow and no matching member function for call to 'connect'

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

                    @frnklu20 Don't put & in front of "this" - "this" is already a pointer. Currently you're passing pointer to pointer which is wrong here.

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

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                    • F frnklu20

                      yeah i fixed it! but it gives me an error in the connect

                      0_1568918552432_c8677482-2b41-434e-aa09-3928e4e4d1c3-image.png

                      if i put the &parameter in the objects it says cannot take the adress of an rvalue of type MainWindow and no matching member function for call to 'connect'

                      Pl45m4P Online
                      Pl45m4P Online
                      Pl45m4
                      wrote on last edited by
                      #17
                      This post is deleted!
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