如果您正在使用材质组件主题，您可以通过将背景颜色设置为透明，然后将布局的背景设置为四舍五入来覆盖BottomSheetDialog的默认行为。

    <style name="Theme.MyApp" parent="Theme.MaterialComponents.DayNight.DarkActionBar">
        <!-- Customize your theme here. -->
        <item name="bottomSheetDialogTheme">@style/BottomSheetDialog</item>
    </style>

    <style name="BottomSheetDialog" parent="ThemeOverlay.MaterialComponents.BottomSheetDialog">
        <item name="bottomSheetStyle">@style/bottomSheetStyleWrapper</item>
    </style>

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

rounded_corner.xml:

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <solid android:color="@color/white"/>
    <corners android:topLeftRadius="26dp"
        android:topRightRadius="26dp"/>

</shape>

然后将形状应用到你的底部表格根布局的背景:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/rounded_corner">

    <!-- 
       other layout components
     -->

</LinearLayout>

注意，如果你在底部表单布局中使用Webview这样的组件，你可能无法实现预期的圆角，因为Webview有一个默认的白色背景。在这种情况下，你可以像这样简单地删除背景:

webView.setBackgroundColor(0);

Koma Yip回答的另一个问题对我有用，你应该试试。

在drawable中创建一个xml，比如dialog_bg.xml <？XML版本="1.0"编码="utf-8"?> <形状xmlns: android = " http://schemas.android.com/apk/res/android " > <固体android:颜色= " @color /白色" / > <corners android:半径="30dp" /> <填充 android:左= " 10 dp” android:顶级= " 10 dp” android:对= " 10 dp” android:底部= " 10 dp " / > < / >形状

把这个放在你的布局XML根节点中:

将其设置为布局XML中的背景 android:背景= " @drawable / dialog_bg”

在onCreateView()中放入:

将对话框的背景设置为透明 dialog.getWindow()。setBackgroundDrawable(新ColorDrawable (Color.TRANSPARENT));

setupDialog()是RestrictedApi。最简单的解决方案:1.3.0-beta01，不涉及主题:

res / drawable - bs_background:

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

public class MyBsDialogFrag extends BottomSheetDialogFragment {

@Override
  public void onViewCreated(View view, Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    ((View) view.getParent()).setBackgroundResource(R.drawable.bs_background);
  }

}

你必须改变底部的主题，以实现顶部圆形布局

创建一个自定义绘制background_bottom_sheet_dialog_fragment.xml:

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

然后在styles.xml上使用drawable作为背景覆盖bottomSheetDialogTheme:

<!--Bottom sheet-->
<style name="BottomSheet" parent="@style/Widget.Design.BottomSheet.Modal">
    <item 
    name="android:background">@drawable/background_bottom_sheet_dialog_fragment
    </item>
</style>

<style name="BaseBottomSheetDialog" 
    parent="@style/Theme.Design.Light.BottomSheetDialog">
    <item name="android:windowIsFloating">false</item>
    <item name="bottomSheetStyle">@style/BottomSheet</item>
</style>

<style name="BottomSheetDialogTheme" parent="BaseBottomSheetDialog" />

这将改变你的底页的背景布局

BottomSheetDialog

class SheetFragment() : BottomSheetDialogFragment() {

    lateinit var binding: SheetFragmentBinding;

  override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
    val dialog = super.onCreateDialog(savedInstanceState) as BottomSheetDialog;
    val view = View.inflate(context, R.layout.fragment_bottom_sheet, null);

    binding = DataBindingUtil.bind(view)!!;
    binding.viewModel = SheetFragmentVM();

    dialog.setContentView(view);

    var bottomSheetBehavior = BottomSheetBehavior.from(view.parent as View);
    bottomSheetBehavior.setPeekHeight(BottomSheetBehavior.PEEK_HEIGHT_AUTO);

    bottomSheetBehavior.setBottomSheetCallback(object : 
     BottomSheetBehavior.BottomSheetCallback() {
        override fun onStateChanged(bottomSheet: View, newState: Int) {
            if (BottomSheetBehavior.STATE_EXPANDED == newState) {
               // do on STATE_EXPANDED
            }
            if (BottomSheetBehavior.STATE_COLLAPSED == newState) {
                // do on STATE_COLLAPSED
            }

            if (BottomSheetBehavior.STATE_HIDDEN == newState) {
                dismiss()

            }
        }

        override fun onSlide(bottomSheet: View, slideOffset: Float) {
           // do on slide
        }
    })

    return dialog
}

在你的BottomsheetDialogFragment类中添加这两个方法。

public void setDialogBorder(Dialog dialog) {
        FrameLayout bottomSheet = (FrameLayout) dialog.getWindow().findViewById(android.support.design.R.id.design_bottom_sheet);
        bottomSheet.setBackground(new ColorDrawable(Color.TRANSPARENT));
        setMargins(bottomSheet, 10, 0, 10, 20);
    }

    private void setMargins(View view, int left, int top, int right, int bottom) {
        if (view.getLayoutParams() instanceof ViewGroup.MarginLayoutParams) {
            ViewGroup.MarginLayoutParams p = (ViewGroup.MarginLayoutParams) view.getLayoutParams();
            p.setMargins(left, top, right, bottom);
            view.requestLayout();
        }
    }

现在调用你的BottomsheetDialogFragment类的setupDialog()方法中的setDialogBorder(dialog)方法。

现在在可绘制文件夹中创建一个形状文件。

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <corners android:radius="20dp" />

    <solid android:color="@color/white" />
    <stroke
        android:width="1dp"
        android:color="@color/transparent" />
</shape>

现在在xml文件中设置父视图组对话框视图的背景。

android:background="@drawable/round_border_white"

完成了! !

我今天也检查了同样的事情，是的，你是对的，下面的代码

this.getDialog().getWindow().setBackgroundDrawableResource(R.drawable.charge_layout_background);

这适用于片段背景，所以相反，你应该从对话框窗口获得底部表视图，并改变背景，这里是代码

 @SuppressLint("RestrictedApi")
    @Override
    public void setupDialog(Dialog dialog, int style) {
        super.setupDialog(dialog, style);
        View rootView = getActivity().getLayoutInflater().inflate(R.layout.view_member_info,null,false);
        unbinder = ButterKnife.bind(this, rootView);
        adjustUIComponents();
        dialog.setContentView(rootView);
        FrameLayout bottomSheet = (FrameLayout) dialog.getWindow().findViewById(android.support.design.R.id.design_bottom_sheet);
        bottomSheet.setBackgroundResource(R.drawable.container_background);
    }

这里的底部是你想要改变的实际视图。