I want to create a fully expanded BottomSheetDialogFragment with top rounded corners, following the technique described in this GitHub comment – https://github.com/material-components/material-components-android/issues/1278#issuecomment-844979762

Before displaying the BottomSheetDialogFragment, the app extends fully to the bottom of the screen.

Before showing BottomSheetDialogFragment

However, when the dialog is shown in its fully expanded state, the bottom bar does not extend as expected. Please refer to the attached screenshots for a visual reference.

When showing BottomSheetDialogFragment

Here’s our code snippet.

RoundedCornerBottomSheetDialogFragment.kt

class RoundedCornerBottomSheetDialogFragment : BottomSheetDialogFragment() {
    private lateinit var binding : RoundedCornerBottomSheetDialogFragmentBinding

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
        binding = RoundedCornerBottomSheetDialogFragmentBinding.inflate(inflater, container, false)

        return binding.root
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        val bottomSheet : FrameLayout = dialog?.findViewById(com.google.android.material.R.id.design_bottom_sheet)!!

        // Height of the view
        bottomSheet.layoutParams.height = ViewGroup.LayoutParams.MATCH_PARENT

        // Behavior of the bottom sheet
        val behavior = BottomSheetBehavior.from(bottomSheet)

        behavior.apply {
            state = BottomSheetBehavior.STATE_EXPANDED
        }
    }

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

styles.xml

<resources>
    <style name="RoundedCornerBottomSheetDialogFragmentStyle" parent="@style/ThemeOverlay.MaterialComponents.BottomSheetDialog">
        <item name="bottomSheetStyle">@style/BottomSheet_NoDrawing</item>
    </style>

    <style name="BottomSheet_NoDrawing" parent="Widget.MaterialComponents.BottomSheet">
        <item name="backgroundTint">@android:color/transparent</item>
    </style>
</resources>

rounded_corner_bottom_sheet_dialog_fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.core.widget.NestedScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:background="@drawable/rounded_top_corners_background"

    android:id="@+id/scroll_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fillViewport="true">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">
        <Button
            android:layout_width="wrap_content"
            android:layout_height="56dp"
            android:text="Hello 1" />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="56dp"
            android:text="Hello 2" />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="56dp"
            android:text="Hello 3" />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="56dp"
            android:text="Hello 4" />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="56dp"
            android:text="Hello 5" />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="56dp"
            android:text="Hello 6" />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="56dp"
            android:text="Hello 7" />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="56dp"
            android:text="Hello 8" />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="56dp"
            android:text="Hello 9" />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="56dp"
            android:text="Hello 10" />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="56dp"
            android:text="Hello 11" />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="56dp"
            android:text="Hello 12" />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="56dp"
            android:text="Hello 13" />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="56dp"
            android:text="Hello 14" />
    </LinearLayout>
</androidx.core.widget.NestedScrollView>

May I know, how I can resolve this issue, to ensure our app remains edge-to-edge?

The complete workable demo can be downloaded from : https://github.com/yccheok/RoundedCornerBottomSheetDialogFragment