Always rounded corners

Dialog.kt

    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
        val dialog = super.onCreateDialog(savedInstanceState) as BottomSheetDialog
        dialog.behavior.addBottomSheetCallback(object : BottomSheetBehavior.BottomSheetCallback() {
            override fun onStateChanged(bottomSheet: View, newState: Int) {
                Timber.d("State changed $newState")
                if (newState == BottomSheetBehavior.STATE_EXPANDED) {
                    Timber.d("State is expanded :D")
                    val shape = createShape(bottomSheet)
                    ViewCompat.setBackground(bottomSheet, shape)
                }
            }

            override fun onSlide(bottomSheet: View, slideOffset: Float) = Unit
        })
        return dialog
    }

    private fun createShape(view: View): MaterialShapeDrawable {
        val model = ShapeAppearanceModel.builder(requireContext(), 0, R.style.Widget_App_ShapeAppearanceBottomSheetDialog)
            .build()

        val current = view.background as MaterialShapeDrawable
        val next = MaterialShapeDrawable(model)

        next.initializeElevationOverlay(context)
        next.fillColor = current.fillColor
        next.tintList = current.tintList
        next.elevation = current.elevation
        next.strokeWidth = current.strokeWidth
        next.strokeColor = current.strokeColor

        return next
    }

styles.xml

    <style name="ThemeOverlay.App.BottomSheetDialog" parent="@style/ThemeOverlay.MaterialComponents.BottomSheetDialog">
        <item name="bottomSheetStyle">@style/Widget.App.BottomSheet</item>
    </style>

    <style name="Widget.App.BottomSheet" parent="Widget.MaterialComponents.BottomSheet">
        <item name="shapeAppearanceOverlay">@style/Widget.App.ShapeAppearanceBottomSheetDialog</item>
    </style>
    
     <style name="Widget.App.ShapeAppearanceBottomSheetDialog" parent="">
        <item name="cornerFamily">rounded</item>
        <item name="cornerSizeTopRight">16dp</item>
        <item name="cornerSizeTopLeft">16dp</item>
        <item name="cornerSizeBottomRight">0dp</item>
        <item name="cornerSizeBottomLeft">0dp</item>
    </style>