我使用的是retrofit，其中我有列表类型的请求。

public RequestBody(String msisdn, List<RoutePlanDayRequests> routePlanDayRequests ) {
        this.msisdn = msisdn;
        this.routePlanDayRequests = routePlanDayRequests;
    }

所以这个RoutePlanDayRequests有以下pojo类。

public class RoutePlanDayRequests {

    private String status;

    private String oldDay;

    private String neweDay;

    public String getOldDay() {
        return oldDay;
    }

    public void setOldDay(String oldDay) {
        this.oldDay = oldDay;
    }

    public String getNeweDay() {
        return neweDay;
    }

    public void setNeweDay(String neweDay) {
        this.neweDay = neweDay;
    }
}

所以我调用了一个web服务来显示adapter中的列表。现在我在adapter类中得到了响应，并在MainActivity中得到了***提交按钮。***所以当我更改其他日子的微调器并提交时，如何从adapter中获得这些项目并在MainActivity中传递数据？
因为在适配器类中，它有spinner，其中项目根据spinner选择进行更改。所以这些项目在更改时需要提交。但问题是提交按钮在MainActivity中。那么如何在MainActivity中传递这些项目值？
MainActivity.class:

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
 setcontentView(R.layout.main);

initialLoadingServiceList(); //this is to load initial items

 submitChangeRequest.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //here I have been strucked.
                updateServiceList();
            }
        });

 private void updateServiceList() {
        List<RoutePlanDayRequests> request = null;
        //strucked to get the spinner values to pass in request.
        RetrofitInstance.getInstance(this)
                .create(RoutePlanService.class)
                .getSaveRoutePlanDay(new SaveDayRequest(new RequestBody("",request)) //here I need to pass the changed item values from adapter to here. 
    }
}

//Hope you got it my requirement. 

public void initialLoadingServiceList(){
//skipping service list.. 

    RoutePlanVisitChangeAdapter adapter = new RoutePlanVisitChangeAdapter(retailers, RoutePlanVisitChangeActivity.this);
                                        mRecyclerView.setAdapter(adapter);

}

}

适配器类别：

public class RoutePlanVisitChangeAdapter extends RecyclerView.Adapter<RoutePlanVisitChangeAdapter.RoutePlanVisitChangeView> {
    private List<Retailers> mList;
    private Context context;
    private String[] daysList = {"MON", "TUE", "WED", "THU", "FRI", "SAT"};

    public RoutePlanVisitChangeAdapter(List<Retailers> list, Context context) {
        this.mList = list;
        this.context = context;
    }

    @Override
    public RoutePlanVisitChangeView onCreateViewHolder(ViewGroup parent, int viewType) {
        View view;
        view = LayoutInflater.from(parent.getContext()).inflate(R.layout.route_plan_visit_change_row, parent, false);
        return new RoutePlanVisitChangeView(view);
    }

    @Override
    public void onBindViewHolder(RoutePlanVisitChangeView holder, int position) {
        Retailers routePlanVisitChange = mList.get(position);
        holder.retailerName.setText(routePlanVisitChange.getName());
        holder.retailerNumber.setText(routePlanVisitChange.getMsisdn());
        holder.fromDay.setText(routePlanVisitChange.getRoutePlanDayOfWeek());
        String profileUrl = routePlanVisitChange.getProfileImage().getImageUrl();
        Glide.with(context)
                .load(profileUrl)
                .placeholder(R.drawable.ic_default_profile)
                .error(R.drawable.ic_default_profile)
                .into((holder.profileImage));

        String getRoutePlanDay = routePlanVisitChange.getRoutePlanDayOfWeek().toUpperCase();
        List<String> asSet = new ArrayList<String>(Arrays.asList(daysList));
        asSet.remove(getRoutePlanDay);
        String[] newDayList = asSet.toArray(new String[]{});
        ArrayAdapter updatedData = new ArrayAdapter(context, android.R.layout.simple_spinner_item, newDayList);
        updatedData.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        holder.toDay.setAdapter(updatedData); //so now i changed the values in spinner. I need to update in button click in main activity
        String selectedSpinner = holder.toDay.getSelectedItem().toString();
    }

    @Override
    public int getItemCount() {
        if (mList == null)
            return 0;
        return mList.size();
    }

    public class RoutePlanVisitChangeView extends RecyclerView.ViewHolder {

        public TextView retailerName;
        public TextView retailerNumber;
        public AppCompatButton fromDay;
        public Spinner toDay;
        public CircleImageView profileImage;

        public RoutePlanVisitChangeView(View view) {
            super(view);
            retailerName = (TextView) 
            view.findViewById(R.id.recycle_txt_acc_name);
            retailerNumber = (TextView) 
            view.findViewById(R.id.recycle_txt_acc_num);
            fromDay = (AppCompatButton) view.findViewById(R.id.from_day);
            toDay = (Spinner) view.findViewById(R.id.to_day);
            profileImage = (CircleImageView) view.findViewById(R.id.recycle_profile);
            //toDay = (AppCompatButton) view.findViewById(R.id.to_day);
        }
    }
    public Retailers getItem(int position) {
        return mList.get(position);
        }
     }
   }

请建议/解决我的问题，请。如何从适配器类中获取MainActivity中的项目。