android 반원 그리기 DrawArc

class ArcView : View {

    constructor(context: Context) : super(context)
    constructor(context: Context, attributeSet: AttributeSet) : super(context, attributeSet)
    constructor(context: Context, attributeSet: AttributeSet, defStyleAttr: Int) : super(
        context,
        attributeSet,
        defStyleAttr
    )

    private val radius = 30
    private val leftPaint = Paint(Paint.ANTI_ALIAS_FLAG)
    private val rightPaint = Paint(Paint.ANTI_ALIAS_FLAG)

    @SuppressLint("DrawAllocation")
    override fun onDraw(canvas: Canvas?) {
        super.onDraw(canvas)

        val oval = RectF()
        val centerX = width * 0.5.toFloat()
        val centerY = height * 0.5.toFloat()
        oval.set(
            centerX - radius,
            centerY - radius,
            centerX + radius,
            centerY + radius
        )

        leftPaint.style = Paint.Style.FILL
        leftPaint.color = Color.parseColor("#800080")
        rightPaint.style = Paint.Style.FILL
        rightPaint.color = Color.parseColor("#ff0000")

        //startAngle : 어디서 시작?
        //sweepAngle : startAngle 에서 시작해서 , sweepAngle만큼 돌려라
        //startAngle 에서 시작해서 , sweepAngle까지 돌려라 아님 주의 !!
        //useCenter : false - 호 , true - 부채꼴 
        canvas?.drawArc(oval, 90f, 180f, false, leftPaint) //왼쪽 반원
        canvas?.drawArc(oval, 270f, 180f, false, rightPaint) //오른쪽 반원
    }
}

startAngle 참고

참고블로그