Android BottomSheetDialogFragment 添加顶部圆角阴影，并且背景不带阴影

: BottomSheetDialogFragment()  内重写getTheme方法

    override fun getTheme(): Int {
        return R.style.CustomBottomSheetDialogTheme
    }

    <style name="CustomBottomSheetDialogTheme" parent="Theme.MaterialComponents.Light.BottomSheetDialog">
        <item name="bottomSheetStyle">@style/CustomBottomSheetStyle</item>
        <!--        背景不带阴影-->
        <item name="android:backgroundDimEnabled">false</item>
    </style>

    <style name="CustomBottomSheetStyle" parent="Widget.MaterialComponents.BottomSheet">
        <item name="android:background">@drawable/rounded_bottom_sheet</item>
    </style>

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <solid android:color="@android:color/white"/>
    <corners android:topLeftRadius="16dp"
        android:topRightRadius="16dp"
        android:bottomRightRadius="0dp"
        android:bottomLeftRadius="0dp"/>
</shape>

onCreateDialog 中

        dialog.setOnShowListener { dialog ->
            val d = dialog as BottomSheetDialog
            val bottomSheet = d.findViewById<View>(R.id.design_bottom_sheet) as FrameLayout?
            // 设置圆角背景
//            bottomSheet?.background = ContextCompat.getDrawable(requireContext(), R.drawable.rounded_bottom_sheet_with_shadow)

            // 创建一个带有圆角和阴影的背景
            val radius = resources.getDimension(R.dimen.dimens_16dp)
            val shapeAppearanceModel =
                ShapeAppearanceModel.builder().setTopLeftCorner(CornerFamily.ROUNDED, radius)
                    .setTopRightCorner(CornerFamily.ROUNDED, radius).build()
            val materialShapeDrawable = MaterialShapeDrawable(shapeAppearanceModel).apply {
                fillColor = ColorStateList.valueOf(
                    ContextCompat.getColor(
                        requireContext(), android.R.color.white
                    )
                )
                elevation = resources.getDimension(R.dimen.dimens_16dp)
                shadowCompatibilityMode = MaterialShapeDrawable.SHADOW_COMPAT_MODE_ALWAYS
            }

            // 设置圆角背景和阴影
            bottomSheet?.background = materialShapeDrawable


            if (isExpand) {
// 完全展开
                BottomSheetBehavior.from(bottomSheet!!).state = BottomSheetBehavior.STATE_EXPANDED
            } else {
                BottomSheetBehavior.from(bottomSheet!!).state = BottomSheetBehavior.STATE_COLLAPSED
            }
        }