AnimateWin

 private val path = Path()
..
    override fun onDraw(canvas: Canvas) {
        super.onDraw(canvas)
        drawVerticalLines(canvas)
        drawHorizontalLines(canvas)
        drawSquareStates(canvas)
        if (shouldAnimate) { <--------Check Here
            canvas.drawPath(path, paint) // path is storing our line
        }
        if (touching) {
            drawHighlightRectangle(canvas)
        }
    }
    
   fun animateWin(x1: Int, y1: Int, x3: Int, y3: Int) { // will be called from activity or fragment
        winCoordinates = arrayOf(x1, y1, x3, y3) // first and last coordinate of winning line
        if (winCoordinates[0] < 0) return
        val centerX = squares[winCoordinates[0]][winCoordinates[1]].exactCenterX()
        val centerY = squares[winCoordinates[0]][winCoordinates[1]].exactCenterY()
        val centerX2 = squares[winCoordinates[2]][winCoordinates[3]].exactCenterX()
        val centerY2 = squares[winCoordinates[2]][winCoordinates[3]].exactCenterY()

        path.reset()
        path.moveTo(centerX, centerY) // moving to centre of first square
        path.lineTo(centerX2, centerY2) // creating a line till centre of last square 
        shouldAnimate = true
        invalidate();
    }