The BottomSheetDialog
is a dialog styled as a bottom sheet
Just use:
//Create a new BottomSheetDialog
BottomSheetDialog dialog = new BottomSheetDialog(context);
//Inflate the layout R.layout.my_dialog_layout
dialog.setContentView(R.layout.my_dialog_layout);
//Show the dialog
dialog.show();
In this case you don't need to attach a BottomSheet behavior.