创建一个自定义的圆角绘图，并将其设置为你的BottomSheetDialogFragment的布局根的背景

<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">

<solid android:color="@color/colorPrimary" />

<corners
    android:bottomLeftRadius="0dp"
    android:bottomRightRadius="0dp"
    android:topLeftRadius="12dp"
    android:topRightRadius="12dp" />

</shape>

然后简单地将下面的代码添加到您的BottomSheetDialogFragment类

@Override
public void setupDialog(Dialog dialog, int style) {
    super.setupDialog(dialog, style);
    View contentView = View.inflate(getContext(), 
R.layout.fragment_bottom_sheet, null);
    dialog.setContentView(contentView);

    CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) ((View) contentView.getParent())
            .getLayoutParams();
    CoordinatorLayout.Behavior behavior = params.getBehavior();
    ((View) contentView.getParent()).setBackgroundColor(ContextCompat.getColor(getContext(), android.R.color.transparent));
}

你甚至可以像下面这样使用参数来设置边距

params.setMargins(50, 0, 50, 0);

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! !

添加圆角形状，使其为你的根布局的背景

<?xml version="1.0" encoding="utf-8" ?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
 <corners
    android:topLeftRadius="@dimen/padding_margin_16_dp"
    android:topRightRadius="@dimen/padding_margin_16_dp" />
 <solid android:color="@color/white" />
</shape>

在你的BottomSheetDialogFragment上使背景透明

override fun onActivityCreated(savedInstanceState: Bundle?) {
    super.onActivityCreated(savedInstanceState)
    (view?.parent as View).setBackgroundColor(Color.TRANSPARENT)
}

它的工作为约束布局，框架布局，线性布局，相对布局。

这对我很管用。

创建一个背景绘图(例如命名为shape_rounded_dialog):

<shape xmlns:android="http://schemas.android.com/apk/res/android"
       android:shape="rectangle">

    <solid android:color="@color/color_white" />
    <corners android:topLeftRadius="16dp"
             android:topRightRadius="16dp" />
</shape>

添加下面的样式:

<style name="AppBottomSheetDialogTheme" 
       parent="Theme.MaterialComponents.Light.BottomSheetDialog">

    <item name="bottomSheetStyle">@style/CustomBottomSheetStyle</item>
</style>

<style name="CustomBottomSheetStyle" 
       parent="Widget.Design.BottomSheet.Modal">

    <item name="android:background">@drawable/shape_rounded_dialog</item>
</style>

在你的DialogFragment中，重写getTheme()方法来返回你的样式。

@Override
public int getTheme() {
    return R.style.AppBottomSheetDialogTheme;
}

步骤1:

创建一个命名为rounded_background.xml的res/drawable:

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
  android:shape="rectangle">
  <corners
    android:topLeftRadius="32dp"
    android:topRightRadius="32dp" />
  <solid android:color="#D81B60" />
</shape>

步骤2:

创建这个样式来删除对话框背景:

<style name="NoBackgroundDialogTheme" parent="Theme.AppCompat.Light.Dialog">
    <item name="android:windowBackground">@null</item>
</style>

步骤3:

使用setBackgroundResource()将可绘制对象设置为对话框的根视图，并通过覆盖getTheme()方法设置样式

Java:

public class MyDialogFragment extends BottomSheetDialogFragment {

    @Override
    public int getTheme() {
        return R.style.NoBackgroundDialogTheme;
    }

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

        View view = View.inflate(requireContext(), R.layout.bottom_sheet_profile, null);
        view.setBackgroundResource(R.drawable.rounded_background);
        return view;

    }
}

科特林：

class MyDialogFragment : BottomSheetDialogFragment() {

    override fun getTheme() = R.style.NoBackgroundDialogTheme

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View {

        val view: View = View.inflate(requireContext(), R.layout.bottom_sheet_profile, null)
        view.setBackgroundResource(R.drawable.rounded_background)
        return view
    }

}

结果:

如果(view.setBackgroundResource(R.drawable.rounded_background))这一行不能工作，然后尝试设置片段的Xml格式的背景。

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。