如何更改Listview按钮名称在自定义适配器类中发送服务器请求后？

Question

最近我正在开发一个基于在线的学生教师通信应用程序.在这个应用程序中,有一部分学生必须向教师发送要求在课堂上添加的内容.

这是自定义适配器getView代码,我使用listview custiom按钮发送请求.我想将asynctask代码放在这个适配器类中.但我无法做到这一点.内部listview onclick按钮方法无法识别asynctask方法.所以我把asynctask方法放在另一个类中.我想在此适配器类中放置asyntask方法,因为我想在onPostExecute方法中发送请求后将按钮名称"Request"更改为"Sent".我手动更改了按钮名称,但我想确保用户100%发送请求.所以请告诉我在哪里必须将asynctask方法放在这个适配器类中,以便我可以更改按钮名称.百万先谢谢.

package project.cc.student;
import java.util.ArrayList;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import com.example.connectifyclassroom.R;
import android.content.Context;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class SubjectAdapter extends ArrayAdapter<Subject> {
    ArrayList<Subject> contactList;
    LayoutInflater vi;
    int Resource;
    ViewHolder holder;
    int studentID;
    SendRequest sendRequest;
    String requestUrl;
    ArrayList<NameValuePair> params;
    public SubjectAdapter(Context context, int resource, ArrayList<Subject> objects,int studentID) {
        super(context, resource, objects);
        vi = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        Resource = resource;
        contactList = objects;
        this.studentID = studentID;
        Log.d("bug", "studentID" + studentID);
        params = new ArrayList<NameValuePair>();

    }
        @Override
        public View getView( final int position, View convertView, ViewGroup parent) {
            // convert view = design
            View v = convertView;
            if (v == null) {
                holder = new ViewHolder();
                v = vi.inflate(Resource, null);
                holder.tvSubject = (TextView) v.findViewById(R.id.tvSujectName);
                holder.tvTeacher = (TextView) v.findViewById(R.id.tvTeacherName);
                holder.btSendRequest =  (Button) v.findViewById(R.id.bt_send_subject_request);
                holder.btSendRequest.setOnClickListener(new Button.OnClickListener() {

                    @Override
                    public void onClick(View view) {
                        // TODO Auto-generated method stub

                        Integer pos = (Integer)view.getTag();
                        Button b = (Button) view;
                        sendRequest = new SendRequest();
                        Toast.makeText(getContext(),"Please Wait...", Toast.LENGTH_SHORT).show();

                        params.add(new BasicNameValuePair("studentID", Integer.toString(studentID)));
                        params.add(new BasicNameValuePair("teacherID", Integer.toString(contactList.get(pos).getTeacherUid())));
                        params.add(new BasicNameValuePair("subjectID", Integer.toString(contactList.get(pos).getSubjectUid())));
                        sendRequest.setPair(params);
                        sendRequest.startRequest();
                        Toast.makeText(getContext(),"Request Sent", Toast.LENGTH_SHORT).show();
                        b.setText("Sent");



                    }
                });
                v.setTag(holder);
            } else {
                holder = (ViewHolder) v.getTag();
            }

        holder.tvSubject.setText(contactList.get(position).getSubject());
        holder.tvTeacher.setText(contactList.get(position).getTeacher());
        holder.btSendRequest.setTag(position);

        return v;

    }

    static class ViewHolder {
        public TextView tvSubject;
        public TextView tvTeacher;
        public Button btSendRequest;

    }
}