Let's add a new private member called m_jumpAnimation of the QPropertyAnimation * type, and initialize it in the constructor of MyScene:
m_jumpAnimation = new QPropertyAnimation(this); m_jumpAnimation->setTargetObject(this); m_jumpAnimation->setPropertyName("jumpFactor"); m_jumpAnimation->setStartValue(0); m_jumpAnimation->setKeyValueAt(0.5, 1); m_jumpAnimation->setEndValue(0); m_jumpAnimation->setDuration(800); m_jumpAnimation->setEasingCurve(QEasingCurve::OutInQuad);