Rotary knob constructor

RotaryKnobView.kt

class RotaryKnobView @JvmOverloads constructor(
    context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
) : RelativeLayout(context, attrs, defStyleAttr), GestureDetector.OnGestureListener {
    private val gestureDetector: GestureDetectorCompat
    private var maxValue = 99
    private var minValue = 0
    var listener: RotaryKnobListener? = null
    var value = 50
    private var knobDrawable: Drawable? = null
    private var divider = 300f / (maxValue - minValue)