private void Awake()
{
PointerEventListener sliderPointerListener = slider.gameObject.AddComponent <PointerEventListener>();
sliderPointerListener.PointerDown += (ev) => sliderFocused = true;
sliderPointerListener.PointerUp += (ev) => sliderFocused = false;
slider.onValueChanged.AddListener(SliderValueChanged);
}