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Problem in Connecting ctkDoubleSpinBox

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  • Christian EhrlicherC Christian Ehrlicher

    @JonB said in Problem in Connecting ctkDoubleSpinBox:

    &this->SliceController->spinBox

    But according to the error message

    cannot convert argument 1 from 'ctkDoubleSpinBox *' to 'const QObject *

    It's already a pointer so the & is wrong.
    I still think the header for this class is not included where the connect is done so the compiler doesn't know that ctkDoubleSpinBox is derived from QObject.

    M Offline
    M Offline
    Meera Hadid
    wrote on last edited by
    #13

    @Christian-Ehrlicher

    • I did include #include <ctkDoubleSpinBox.h>
    jsulmJ 1 Reply Last reply
    0
    • M Meera Hadid

      @Christian-Ehrlicher

      • I did include #include <ctkDoubleSpinBox.h>
      jsulmJ Offline
      jsulmJ Offline
      jsulm
      Lifetime Qt Champion
      wrote on last edited by
      #14

      @Meera-Hadid Fix your connect as suggested by @JonB and try again

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

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      • JonBJ JonB

        @Meera-Hadid said in Problem in Connecting ctkDoubleSpinBox:

        I am getting a syntax error when I use this: this->SliceController->&spinBox

        This is not legal C++. It should be:

        &this->SliceController->spinBox
        

        Whether you want the & depends on whether spinbox is already a pointer or not (I think yours is a pointer, in which case you would not want it?)

        M Offline
        M Offline
        Meera Hadid
        wrote on last edited by
        #15

        @JonB

        • Yes when I tried without using & it was raising an error that cannot convert from 'ctkDoubleSpinBox *' to 'const QObject *'

        @jsulm

        • The issue is not getting pointer the issue is it cannot convert from 'ctkDoubleSpinBox *' to 'const QObject *'
        JonBJ jsulmJ 3 Replies Last reply
        0
        • M Meera Hadid

          @JonB

          • Yes when I tried without using & it was raising an error that cannot convert from 'ctkDoubleSpinBox *' to 'const QObject *'

          @jsulm

          • The issue is not getting pointer the issue is it cannot convert from 'ctkDoubleSpinBox *' to 'const QObject *'
          JonBJ Offline
          JonBJ Offline
          JonB
          wrote on last edited by
          #16

          @Meera-Hadid said in Problem in Connecting ctkDoubleSpinBox:

          @JonB

          Yes when I tried without using & it was raising an error that cannot convert from 'ctkDoubleSpinBox *' to 'const QObject *'

          @jsulm

          The issue is not getting pointer the issue is it cannot convert from 'ctkDoubleSpinBox *' to 'const QObject *'

          Inserting a & randomly will not help. The message already tells that pointer-ness is not the issue.

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          • M Meera Hadid

            @JonB

            • Yes when I tried without using & it was raising an error that cannot convert from 'ctkDoubleSpinBox *' to 'const QObject *'

            @jsulm

            • The issue is not getting pointer the issue is it cannot convert from 'ctkDoubleSpinBox *' to 'const QObject *'
            jsulmJ Offline
            jsulmJ Offline
            jsulm
            Lifetime Qt Champion
            wrote on last edited by
            #17

            @Meera-Hadid said in Problem in Connecting ctkDoubleSpinBox:

            The issue is not getting pointer the issue is it cannot convert from 'ctkDoubleSpinBox *' to 'const QObject *'

            Do you mean you get same error message if you use new connect syntax?

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

            1 Reply Last reply
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            • M Meera Hadid

              @JonB

              • Yes when I tried without using & it was raising an error that cannot convert from 'ctkDoubleSpinBox *' to 'const QObject *'

              @jsulm

              • The issue is not getting pointer the issue is it cannot convert from 'ctkDoubleSpinBox *' to 'const QObject *'
              JonBJ Offline
              JonBJ Offline
              JonB
              wrote on last edited by JonB
              #18

              @Meera-Hadid
              Please do the following:

              • First, delete all the files from the build output directory. Do a fresh qmake followed by a build. Does the error still occur?
              • From the line number in the error message, are you quite sure it is on the connect() statement you have shown, and not some other?
              • I believe I already advised this before in answer to the same problem from you in another thread: on the line above the connect() put in
              const QObject *temp = this->SliceController->spinBox;
              

              Does that error (show message)?

              M 1 Reply Last reply
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              • JonBJ JonB

                @Meera-Hadid
                Please do the following:

                • First, delete all the files from the build output directory. Do a fresh qmake followed by a build. Does the error still occur?
                • From the line number in the error message, are you quite sure it is on the connect() statement you have shown, and not some other?
                • I believe I already advised this before in answer to the same problem from you in another thread: on the line above the connect() put in
                const QObject *temp = this->SliceController->spinBox;
                

                Does that error (show message)?

                M Offline
                M Offline
                Meera Hadid
                wrote on last edited by
                #19

                @JonB

                • const QObject *temp = this->SliceController->spinBox;
                  this works
                • But the signal SIGNAL(valueChanged(double)) doesn't get activated (QLabel value doesn't change). Is it because temp is returing nullptr?
                JonBJ 1 Reply Last reply
                0
                • M Meera Hadid

                  @JonB

                  • const QObject *temp = this->SliceController->spinBox;
                    this works
                  • But the signal SIGNAL(valueChanged(double)) doesn't get activated (QLabel value doesn't change). Is it because temp is returing nullptr?
                  JonBJ Offline
                  JonBJ Offline
                  JonB
                  wrote on last edited by
                  #20

                  @Meera-Hadid

                  Is it because temp is returing nullptr?

                  Pardon? Are you saying this->SliceController->spinBox == nullptr at the time you execute the connect() statement?

                  Separately, put a qDebug() statement as the first thing in your void qMRMLSliceWidget::updateLabel().

                  M 1 Reply Last reply
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                  • JonBJ JonB

                    @Meera-Hadid

                    Is it because temp is returing nullptr?

                    Pardon? Are you saying this->SliceController->spinBox == nullptr at the time you execute the connect() statement?

                    Separately, put a qDebug() statement as the first thing in your void qMRMLSliceWidget::updateLabel().

                    M Offline
                    M Offline
                    Meera Hadid
                    wrote on last edited by
                    #21

                    @JonB said in Problem in Connecting ctkDoubleSpinBox:

                    Separately, put a qDebug() statement as the first thing in your void qMRMLSliceWidget::updateLabel().

                    Yes I did but that statement is not getting printed/executed

                    JonBJ 1 Reply Last reply
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                    • M Meera Hadid

                      @JonB said in Problem in Connecting ctkDoubleSpinBox:

                      Separately, put a qDebug() statement as the first thing in your void qMRMLSliceWidget::updateLabel().

                      Yes I did but that statement is not getting printed/executed

                      JonBJ Offline
                      JonBJ Offline
                      JonB
                      wrote on last edited by
                      #22

                      @Meera-Hadid
                      I have asked you other questions. If you don't want to respond to them that is up to you.

                      M 1 Reply Last reply
                      0
                      • JonBJ JonB

                        @Meera-Hadid
                        I have asked you other questions. If you don't want to respond to them that is up to you.

                        M Offline
                        M Offline
                        Meera Hadid
                        wrote on last edited by
                        #23

                        @JonB

                        • First, delete all the files from the build output directory. Do a fresh qmake followed by a build. Does the error still occur?
                          Since there are a lot of files it takes a lot of time to build hence I did not clear the build.
                        • It's my bad that I assumed this->SliceController->spinBox was returning a nullptr. The problem was with slot I changed it.
                        • const QObject *temp = this->SliceController->spinBox; worked for me

                        Thanks everyone for contributing.

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