class MyButton : public QPushButton
{
    Q_OBJECT

private:
    int m_test;

public:
    MyButton(QWidget* Parent = 0) : QPushButton(Parent), m_test(0) {this->ensurePolished();}
    virtual ~MyButton();

    Q_PROPERTY(int test READ getTest WRITE setTest);

    void setTest(int test){m_test = test};
    int getTest() const {return m_test;};
};

    MyButton* my = new MyButton(this);
    qDebug() << my->getTest();//0
    my->setStyleSheet("qproperty-test:5");
    qDebug() << my->getTest();//5

Q_PROPERTY(int test READ getTest WRITE setTest NOTIFY changeTest)
...
signals:
    void changeTest();
...
void APush::setTest(int newValue)
{
    if (m_Test != newValue)
    {
        m_Test = newValue;
        emit changeTest();
    }
}

class testButton : public QPushButton
{
  Q_OBJECT
  Q_PROPERTY (int testProp READ getTestProp WRITE setTestProp)
public:
  explicit testButton (QWidget *parent = 0);
  int getTestProp ()
  {
    return testProp;
  }
  void setTestProp (int pPropVal)
  {
    testProp = pPropVal;
    setText (QString ().setNum (testProp));
  }

protected:
  virtual void mousePressEvent (QMouseEvent * e)
  {
    QPushButton::mousePressEvent (e);
    this->style ()->polish (this);
  }
  virtual void mouseReleaseEvent (QMouseEvent * e)
  {
    QPushButton::mouseReleaseEvent (e);
    this->style ()->polish (this);
  }

private:
  int testProp;
};

testButton::testButton(QWidget *parent) :
    QPushButton(parent)
{
  this->setStyleSheet (QLatin1String ("testButton {qproperty-testProp:1; border:0px;} testButton[down='true'] {qproperty-testProp:3; border:3px solid black;}"));
}