flutter Column里邊Expanded顯示太大的問題

              onTap: () {

                showModalBottomSheet(context: context,builder: (ctx)=>new Column(
                  mainAxisSize: MainAxisSize.min,
                  children: <Widget>[

                Expanded(
                      child:MaterialButton(

效果：

將以上代碼改為 :

              onTap: () {

                showModalBottomSheet(context: context,builder: (ctx)=>new Column(
                  mainAxisSize: MainAxisSize.min,
                  children: <Widget>[

                ListTile(
                      title:MaterialButton(

效果為 :