如何将showModalBottomSheet设置为最初的一半高度，但可扩展和可忽略

Question

以下代码是可以忽略的，但由于colorsList颜色很多，它最初占用了整个高度：

      onPressed: () 
        showModalBottomSheet(
          context: this.context,
          isScrollControlled: true,
          builder: (BuildContext context) 
            return Wrap(
              children: [
                for (List<Color> colors in colorsList)
                  Container(
                    child: Column(
                      mainAxisSize: MainAxisSize.min,
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: <Widget>[
                        Text("$colorsName[colorsList.indexOf(colors)]"),

                        Container(
                          height: 80,
                          child: ListView.builder(
                            padding: EdgeInsets.only(left: 8, right: 8,),
                            scrollDirection: Axis.horizontal,
                            itemCount: colors.length,
                            itemBuilder: (BuildContext context, int index) 
                              return Padding(
                                padding: const EdgeInsets.only(left: 8,),
                                child: FloatingActionButton(
                                  backgroundColor: colors[index],
                                  tooltip: "Choose this color",
                                  onPressed: () 
                                    setState(() 
                                      this.color = colors[index];
                                    );
                                    Navigator.pop(context);
                                  ,
                                ),
                              );
                            ,
                          ),
                        ),
                      ],
                    ),
                  ),
              ],
            );
          
        );
      ,