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Thread: QwtDial and QwtKnob not sending position information

  1. #1
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    Lightbulb QwtDial and QwtKnob not sending position information

    I am new to Qt and Qwt so I apologize in advance for the simplicity of my question. I am using Qt 5

    I created a QwtDial and QwtKnob and wanted to connect a signal to see the value change. I also created a QDial and did the same thing. the signals work correctly when I move the Qdial.

    d_knob = new QwtKnob;
    d_knob->setScale(0,20);
    ui->knobVerticalLayout->addWidget(d_knob);

    connect(d_knob, SIGNAL(d_knob->sliderMoved(double)), this, SLOT(testQwtDialSliderMoved(double)));

    when I run I get the message:
    QObject::connect: No such signal QwtKnob::d_knob->sliderMoved(double) in ..\qwt_test\mainwindow.cpp:51
    QObject::connect: (receiver name: 'MainWindow')

    I am sure I am missing something very simple. I am not getting a signal sent from QwtDial or QwtKnow but I am getting the signal from QDial.

    in my header file:
    public Q_SLOTS:
    void testQDialSliderMoved(int value);
    void testQwtDialSliderMoved(double value);


    any help would be appreciated.

  2. #2
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    Default Re: QwtDial and QwtKnob not sending position information

    Wrong syntax for the connect() statement. Should be:

    Qt Code:
    1. connect(d_knob, SIGNAL(sliderMoved(double)), this, SLOT(testQwtDialSliderMoved(double)));
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    and be sure to define "testQwtDialSliderMoved()" as a slot in your MainWindow class.

    Please use CODE tags when posting code. Click "Go advanced" and then the "#" icon to insert the open/close tag pair. Paste your code between them.

  3. #3
    Join Date
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    Default Re: QwtDial and QwtKnob not sending position information

    all worked perfectly. operator error. Thank you very much. Love Qt awesome!!!

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