let arrowView = ArrowView()
    arrowView.frame = CGRect(x: selectButton.frame.minX, y: selectButton.frame.maxY, width: selectButton.frame.width, height: processButton.frame.minY - selectButton.frame.maxY)
    arrowView.backgroundColor = UIColor.white
    arrowView.viewWithTag(100)
    view.addSubview(arrowView)

let arrowPath = UIBezierPath.bezierPathWithArrowFromPoint(startPoint: startPoint, endPoint: endPoint, tailWidth: 4, headWidth: 8, headLength: 6)
// Only override draw() if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
override func draw(_ rect: CGRect) {
    let fillColor = UIColor.white
    fillColor.setFill()

    arrowPath.lineWidth = 1.0
    let strokeColor = UIColor.blue
    strokeColor.setStroke()

    arrowPath.stroke()
    arrowPath.fill()
}

private var startPoint: CGPoint {
    return CGPoint(x: bounds.midX, y: bounds.minY)
}
private var endPoint: CGPoint {
    return CGPoint(x: bounds.midX, y: bounds.maxY)
}