Make QDial ignore user input

**burnchar** · 10th February 2010, 17:47

I'd appreciate suggestions on an elegant, simple way to make QDials ignore user input but accept programmatic input.

I could make a new class derived from QDial and override several event handlers, but I am curious if I missed some obvious 1-liner or similar.

**caduel** · 10th February 2010, 19:15

setEnabled(false) ?

**burnchar** · 17th February 2010, 16:46

Thank you for the reply. Unfortunately, disabling the control makes it ignore all programmatic input until it is re-enabled. I'd still like to be able to set its position by calling its set functions.

**Lykurg** · 17th February 2010, 17:54

I haven't tried, but following should work:

Subclass QDial
add a custom slot where you set a privat bool (acceptUserInput)
reimp mouse***event, there redirect the event to the base class only if acceptUserInput is true

Should work and in done in < 5 minutes!

**Lykurg** · 17th February 2010, 18:52

I have had 5 minutes time...

Qt Code:

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class MyDial : public QDial
{
public:
    explicit MyDial(QWidget *parent = 0) : QDial(parent), m_enable(true) {}
    void setUserInputEnabled(bool enable)
    {
        m_enable = enable;
        setFocusPolicy(m_enable ? Qt::WheelFocus : Qt::NoFocus);
    }
 
protected:
    void mouseMoveEvent(QMouseEvent *e)
    {
        if(m_enable) QDial::mouseMoveEvent(e);
    }
    void mousePressEvent(QMouseEvent *e)
    {
        if(m_enable) QDial::mousePressEvent(e);
    }
    void mouseReleaseEvent(QMouseEvent *e)
    {
        if(m_enable) QDial::mouseReleaseEvent(e);
    }
    void keyPressEvent(QKeyEvent *e)
    {
        if(m_enable) QDial::keyPressEvent(e);
    }
    void keyReleaseEvent(QKeyEvent *e)
    {
        if(m_enable) QDial::keyReleaseEvent(e);
    }
    void wheelEvent(QWheelEvent *e)
    {
        if(m_enable) QDial::wheelEvent(e);
    }
 
private:
    bool m_enable;
};

class MyDial : public QDial
{
public:
    explicit MyDial(QWidget *parent = 0) : QDial(parent), m_enable(true) {}
    void setUserInputEnabled(bool enable)
    {
        m_enable = enable;
        setFocusPolicy(m_enable ? Qt::WheelFocus : Qt::NoFocus);
    }

protected:
    void mouseMoveEvent(QMouseEvent *e)
    {
        if(m_enable) QDial::mouseMoveEvent(e);
    }
    void mousePressEvent(QMouseEvent *e)
    {
        if(m_enable) QDial::mousePressEvent(e);
    }
    void mouseReleaseEvent(QMouseEvent *e)
    {
        if(m_enable) QDial::mouseReleaseEvent(e);
    }
    void keyPressEvent(QKeyEvent *e)
    {
        if(m_enable) QDial::keyPressEvent(e);
    }
    void keyReleaseEvent(QKeyEvent *e)
    {
        if(m_enable) QDial::keyReleaseEvent(e);
    }
    void wheelEvent(QWheelEvent *e)
    {
        if(m_enable) QDial::wheelEvent(e);
    }

private:
    bool m_enable;
};

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Maybe there are other events you want to disable.

Lykurg