How can get value from each dropdown?

I am selecting the count of son, on the basis of count I created selected number of dropdown I just want to get value from each dropdown dropdown and dropdown count is not fixed. So I want separate value from each dropdown. How can I achieve this.

bool sonVisible = false;
bool sonChecked = false;
String sonCount;

Column(
                      mainAxisAlignment: MainAxisAlignment.start,
                      children: [
                        Row(
                          mainAxisAlignment: MainAxisAlignment.spaceBetween,
                          children: [
                            Flexible(
                                child: CustomListTile(
                              title: 'Son',
                              selected: sonChecked,
                              onChanged: (bool value) {
                                setState(() {
                                  sonChecked = value;
                                  if (sonChecked == true) {
                                    sonVisible = true;
                                  } else {
                                    sonVisible = false;
                                    sonDropDown = false;
                                  }
                                });
                              },
                            )),
                            Flexible(
                                child: Visibility(
                              visible: sonVisible,
                              child: CustomCountDropDown(
                                ageValue: sonCount,
                                onChanged: (val) {
                                  setState(() {
                                    sonCount = val;
                                    sonListCount = int.parse(sonCount);
                                    print(sonCount);
                                    sonDropDown = true;
                                  });
                                },
                                decoration: spinnerDecoration('No of Son'),
                              ),
                            )),
                          ],
                        ),
                        Visibility(
                          visible: sonDropDown,
                          maintainState: true,
                          child: Padding(
                            padding: EdgeInsets.only(top: 1.0.h, left: 3.0.h),
                            child: GridView.builder(
                              itemCount: sonListCount,
                              gridDelegate:
                                  SliverGridDelegateWithFixedCrossAxisCount(
                                crossAxisCount: 2,
                                crossAxisSpacing: 4.0.w,
                                childAspectRatio: MediaQuery.of(context)
                                        .size
                                        .width /
                                    (MediaQuery.of(context).size.height / 5),
                              ),
                              shrinkWrap: true,
                              itemBuilder: (context, index) {
                                return CustomAgeDropDown(
                                  decoration: spinnerDecoration(
                                      'Age Son - ${index + 1}'),
                                  ageValue: (how can I get value ?),
                                  onChanged: (value) {
                                    setState(() {
                                      
                                    });
                                  },
                                );
                              },
                            ),
                          ),
                        ),
                      ],
                    ),

Custom Dropdown for Age

class CustomAgeDropDown extends StatefulWidget {
      final String ageValue;
      final InputDecoration decoration;
      final Function onChanged;
    
    
      CustomAgeDropDown(
          {this.ageValue, this.decoration, this.onChanged});
    
      @override
      _CustomAgeDropDownState createState() => _CustomAgeDropDownState();
    }
    
    class _CustomAgeDropDownState extends State<CustomAgeDropDown> {
      List<String> adultAgeList = List<String>.generate(100, (int index) => '${index+1 * 18}');
    
      @override
      Widget build(BuildContext context) {
        List<DropdownMenuItem> adult = adultAgeList.map((val) => DropdownMenuItem(value: val, child: Text(val,style: GoogleFonts.poppins(),))).toList();
        return DropdownButtonFormField(
          onChanged: widget.onChanged,
          decoration: widget.decoration,
          isDense: true,
          value: widget.ageValue,
          items: adult,
        );
      }
    }

After make check list-tile count dropdown will visible then I choose no son count after choosing no of son count then no of selected count dropdown created. I just want to get value from each dropdown.

Source: Ios Questions