canvas.draw<Figure>仅为第一个视图绘制

我有一个自定义视图:

    class StepView(
        context: Context?,

        @ColorInt
        color: Int,

        private val size: Float
    ) : View(context) {

        private val paint = Paint(Paint.ANTI_ALIAS_FLAG)

        init {
            paint.color = color
            setWillNotDraw(false)
        }

        fun setColor(@ColorInt color: Int) {
            paint.color = color
            invalidate()
        }

        private fun getCenterX() = x + width / 2

        private fun getCenterY() = y + height / 2

        override fun onDraw(canvas: Canvas?) {
            super.onDraw(canvas)

            canvas?.drawCircle(getCenterX(), getCenterY(), size / 2, paint)
        }
    }

    private fun init(stepCount: Int = defaultStepCount, currentStep: Int = defaultCurrentStep) {
        orientation = HORIZONTAL

        removeAllViews()

        for (i in 0 until stepCount) {
            createStepView(i)
        }
    }

    private fun createStepView(index: Int) {
        val stepView = StepView(context, arrayOf(Color.RED, Color.GREEN, Color.BLUE, Color.BLACK)[index], 20f)
        val layoutParams = LayoutParams(20, 20)

        addView(stepView, layoutParams)
    }

canvas?.drawCircle() drawRect() )仅适用于第一个:

第二个和第三个在布局中,但没有绘制(边框来自UiAutomatorViewer; onDraw

如果我打电话 canvas?.drawColor()