Remove rows from listview as well as from my hostinger server database using remove button which is set by Adapter : i want to remove a particular row from database as well as from list view when i click the remove button,i tried but i am not getting the error 

> UserAdapter cannot be cast to android.content.Context

here is my Adapter

    public class UserAdapter extends BaseAdapter implements  OnTaskCompleted{

    Context context;
    UserAdapter userAdapter;
    Bundle b=new Bundle();
    HashMap<Integer, UserSetter> userSettersClassHashMap;
    int layoutResId;
    String email_id="";
    private HashMap<String, String> postDataParams = null;
    TextView fname,lname,uname,empid,emailid,contact,role;

    Button edit,remove;



    public UserAdapter(Context context, HashMap<Integer, UserSetter> userSettersClassHashMap, int layoutResId) {
        this.context = context;
        this.userSettersClassHashMap = userSettersClassHashMap;
        this.layoutResId = layoutResId;
    }

    @Override
    public int getCount() {
        return userSettersClassHashMap.size();
    }

    @Override
    public Object getItem(int position) {

        return userSettersClassHashMap.get(position);
    }

    @Override
    public long getItemId(int position) {
        return 0;
    }

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {

        View view;

        if (convertView == null) {
            LayoutInflater lf = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = lf.inflate(layoutResId, parent, false);
            view = convertView;



        } else {
            view = convertView;
        }
        fname = (TextView) view.findViewById(R.id.fname);
       // lname = (TextView) view.findViewById(R.id.lname);
        //uname = (TextView) view.findViewById(R.id.uname);
       // empid= (TextView) view.findViewById(R.id.empid);
        emailid= (TextView) view.findViewById(R.id.emailid);
        //contact= (TextView) view.findViewById(R.id.contact);
        role= (TextView) view.findViewById(R.id.role);

        remove=(Button) view.findViewById(R.id.remove);

        fname.setText(Html.fromHtml(userSettersClassHashMap.get(position).getFirstname()));
//        lname.setText(Html.fromHtml(userSettersClassHashMap.get(position).getLastname()));
  //      uname.setText(Html.fromHtml(userSettersClassHashMap.get(position).getUsername()));
       // empid.setText(Html.fromHtml(userSettersClassHashMap.get(position).getEmployee_id()));
        emailid.setText(Html.fromHtml(userSettersClassHashMap.get(position).getEmail_id()));
    //    contact.setText(Html.fromHtml(userSettersClassHashMap.get(position).getContact_no()));
        role.setText(Html.fromHtml(userSettersClassHashMap.get(position).getRoleName()));


        remove.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {


                email_id = String.valueOf(emailid.getText());
                Log.v("email adapter", String.valueOf(email_id));
              
                callRemove();
                notifyDataSetChanged();

            }

            public void callRemove() {

                postDataParams = new HashMap<>();
                
                postDataParams.put("email_id", email_id);

                Log.d("postdataparams","->"+postDataParams);
                new WebService(UserAdapter.this, postDataParams, "RemoveList").execute(AppConstants.BASE_URL + AppConstants.REMOVE_DATA);
            }

        });

        return view;

    }


    @Override
    public void onTaskCompleted(JSONObject jsonObject, String result, String TAG) throws Exception {
        if (jsonObject != null) {
            if (jsonObject.has("success"))
            {
                if (jsonObject.optString("success").equalsIgnoreCase("1"))
                {

                    Toast.makeText(context.getApplicationContext(), "User Deleted", Toast.LENGTH_SHORT).show();
                    Intent intent=new Intent(context.getApplicationContext(),User.class);
                    context.startActivity(intent);



                }
            }
            else if (jsonObject.optString("success").equalsIgnoreCase("0"))
            {
                Toast.makeText(context.getApplicationContext(), "failed", Toast.LENGTH_SHORT).show();

            }


        }



    }
}