自定义文本视图文本不可见

我有一个简单的习惯 TextView 添加圆角背景色。然而,文本是不可见的,你可以从绿色的小广场看到。我也尝试在xml文件中设置文本和textcolor,同样的事情。我做错了什么?

class StatusRectView(context: Context, attrs: AttributeSet) : TextView(context, attrs) {

    private var cornerRadius = 0.8f
    private val paint = Paint()
    private var size = 0  

    init {
        paint.isAntiAlias = true
        gravity = Gravity.CENTER
        setTextColor(Color.WHITE)
        text = "D"
    }

    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec)

        size = Math.min(measuredWidth, measuredHeight)
        setMeasuredDimension(size, size)
    }

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

        paint.color = Color.GREEN
        paint.style = Paint.Style.FILL

        val rectF = RectF(0f,  0f, size * 1f, size * 1f)
        canvas.drawRoundRect(rectF, cornerRadius, cornerRadius, paint)
    }
}