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);

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;
}

最简单和最干净的解决方案，对我来说，是把以下4行放在我的片段类的onViewCreated(View View, Bundle savedInstanceState)方法中:

@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
    View bottomSheet = (View) view.getParent();
    bottomSheet.setBackgroundTintMode(PorterDuff.Mode.CLEAR);
    bottomSheet.setBackgroundTintList(ColorStateList.valueOf(Color.TRANSPARENT));
    bottomSheet.setBackgroundColor(Color.TRANSPARENT);
}

这将允许您的自定义绘制圆角，以正确显示一旦设置为您的片段布局的顶层视图的背景。

本质上，这将覆盖默认的BottomSheetFragment属性关于颜色，tintMode和tintList。

使用它，就不需要打乱样式资源。

我找到了一个简单的解决办法。 使用com.google.android.material:material:1.6.1

class MyBottomSheet: BottomSheetDialogFragment() {
    
      override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
            super.onViewCreated(view, savedInstanceState)
            disableShapeAnimation()
        }
    
      @SuppressLint("RestrictedApi", "VisibleForTests")
      private fun disableShapeAnimation() {
            try {
                val dlg = dialog as BottomSheetDialog
                dlg.behavior.disableShapeAnimations()
            } catch (ex: Exception) {
                Log.e("BaseBottomSheet", "disableShapeAnimation Exception:", ex)
            }
        }
}

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。

底页对话框具有弯曲的形状和偷看高度

    <!-- BottomSheet Dialog -->
<style name="BottomSheetDialog" parent="Theme.Design.Light.BottomSheetDialog">
    <item name="bottomSheetStyle">@style/CustomBottomSheet</item>

</style>


<style name="CustomBottomSheet" parent="Widget.MaterialComponents.BottomSheet">
    <item name="shapeAppearanceOverlay">@style/CustomShapeAppearanceBottomSheetDialog</item>
    <item name="behavior_peekHeight">420dp</item>
</style>

<style name="CustomShapeAppearanceBottomSheetDialog" parent="">
    <item name="cornerFamily">rounded</item>
    <item name="cornerSizeTopRight">20dp</item>
    <item name="cornerSizeTopLeft">20dp</item>
    <item name="cornerSizeBottomRight">0dp</item>
    <item name="cornerSizeBottomLeft">0dp</item>

</style>