I set button padding to 0 but the top and bottom still has padding

Question

I have the following code. There's is some preexisting code and I added new changes below. However, I see that in my button, there's some padding on top and bottom. I'm not sure where this is coming from.

class MyButton(context: Context) : Button(context) {
    fun init() {
        setBackgroundColor(Color.parseColor("#880808")) // for testing
        text = context.getString(R.string.some_text)
        setTextColor(ContextCompat.getColor(context, R.color.some_color))
        this.setTextSize(
                TypedValue.COMPLEX_UNIT_DIP, getSizeInDP()
        )
//My new changes below
        isAllCaps = false
        layoutParams = LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT).also {
            it.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM)
            it.setMargins(getMarginSize(), getMarginSize(), getMarginSize(), getMarginSize())
        }
        minWidth = 0
        minHeight = 0
        setPadding(0, 0, 0, 0)
    }

// Pre-existed code
class SomeActivity() { 
    override fun onCreate(savedInstanceState: Bundle?) {
        .....
        val height = (displayMetrics.heightPixels * 0.15).toInt()


        val container = RelativeLayout(this)
        val button = MyButton(this)
        button.init()
        container.addView(button)


        container.setBackgroundColor(Color.TRANSPARENT)
        val myLayoutParams = createContainerLayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
                headerHeight - 30)
        myLayoutParams.topMargin = 30
        container.layoutParams = myLayoutParams
        .....
    }
}

The button has some padding on the top and bottom. I'm not sure where this padding is coming from when I set padding to 0.

Image: