悬停时打开Flutter 下拉按钮

我正在开发一个Ffltter Web应用程序，并且我已经使用了一个Dropdown Button小部件作为我网站的顶部菜单.如何在鼠标悬停时打开下拉按钮.下面是我的下拉按钮

DropdownButton(
                      value: teachingsDropdownValue,
                      icon: SizedBox.shrink(),
                      focusColor: Colors.white,
                      elevation: 0,
                      onTap: (){},
                      underline: Container(
                        height: 2,
                        color: Colors.white,
                      ),
                      items: teachingsItems.map((String items) {
                        return DropdownMenuItem(
                          value: items,
                          child: Text(items,textAlign: TextAlign.center,),
                        );
                      }).toList(),
                      onChanged: (String? newValue) {
                        setState(() {
                          // teachingsDropdownValue = newValue!;
                          if(newValue == "Salivation"){
                            Navigator.of(context).push(MaterialPageRoute(builder: (context) => TeachingsSalivationScreen()));
                          }

                        });
                      },
                    ),