CircleIndicator - Custom View

class CircleIndicator : View {

    private val paint = Paint()

    private var centerX = 0F;
    private var centerY = 0F;
    private var radius = 0F;

    constructor(context: Context) : super(context)

    constructor(context: Context, attrs: AttributeSet) : super(context, attrs)

    override fun onAttachedToWindow() {
        super.onAttachedToWindow()

        paint.color = Color.RED;
        paint.isAntiAlias = true
        paint.style = Style.FILL
    }


    override fun onDraw(canvas: Canvas) {
        super.onDraw(canvas)
        canvas.drawCircle(centerX, centerY, radius, paint)
    }

    override fun onTouchEvent(event: MotionEvent?): Boolean {
        Toast.makeText(context, "Hello !!!", Toast.LENGTH_LONG).show();
        return true;
    }

    override fun onSizeChanged(w: Int, h: Int, oldw: Int, oldh: Int) {
        super.onSizeChanged(w, h, oldw, oldh)
        centerX = w / 2F
        centerY = h / 2F
        radius = if (w < h) w / 2F else h / 2F
    }
}