How to "touch" a slider via script?

I am working on a mobile app. I have a slider that becomes that, when you touch the screen, becomes active and positions itself to your finger (you always touch the knob). However, I cannot move the slider when I move my finger on the screen. The reason it is (I t$$anonymous$$nk) is because it is not recognised as the selected ui component. So my question is how do I move the slider with the same touch that also activated it?