如何重写showModalBottomSheet 方法

重写showModalBottomSheet方法需要继承BottomSheet类，并且覆盖掉showModalBottomSheet方法。具体实现如下：

class MyBottomSheet extends BottomSheet {
  MyBottomSheet({
    required Widget child,
    required BuildContext context,
  }) : super(
          onClosing: () {},
          builder: (BuildContext context) => child,
        );

  @override
  Future<T?> showModalBottomSheet<T>({
    required BuildContext context,
    required WidgetBuilder builder,
    Color? backgroundColor,
    double? elevation,
    ShapeBorder? shape,
    Clip? clipBehavior,
    bool? isScrollControlled,
    bool? useRootNavigator,
    bool? isDismissible,
    bool? enableDrag,
  }) {
    return super.showModalBottomSheet(
      context: context,
      builder: (BuildContext context) {
        return Container(
          padding: EdgeInsets.all(16.0),
          child: builder(context),
        );
      },
      backgroundColor: backgroundColor,
      elevation: elevation,
      shape: shape,
      clipBehavior: clipBehavior,
      isScrollControlled: isScrollControlled,
      useRootNavigator: useRootNavigator,
      isDismissible: isDismissible,
      enableDrag: enableDrag,
    );
  }
}

这样就可以使用MyBottomSheet类来重写showModalBottomSheet方法，同时可以对底部弹出框的样式进行自定义。