کنسل کردن asyn task

سلام

من یه لیست بی پایان با ریسایکرویو ساختم . زمانی که به انتهای  اون مقداری که از سرور می گیریه دوباره از یه کلاس asyntask  فراخوانی میشه . کدها رو در پایین قرار دارم. درست کار میکنه ولی هنگامی که اسکرول سریع میدم غاطی می کنه لودینگ متوقف نمیشه کل و پروسه پایان لیست دیگه متوقف میشه کار نمی کنه . مشکل از کجاس؟ و میخواستم بدونم برای متوقف کردن اجرا کلاس asynctask  چی کار باید کرد؟

public  class home_agahi_server  extends AsyncTask<String,Void,String> {

    private Context c;
    private Activity ac;

    private String state_id;
    private String lim;
    private RecyclerView rec;

    home_agahi3_server mTask = null;
    private final ReentrantLock lock = new ReentrantLock();
    private final Condition tryAgain = lock.newCondition();
    private volatile boolean finished = false;


    public home_agahi_server(Context c,Activity ac,String lim
    ){
        this.c=c;
        this.ac=ac;

        this.lim=lim;
        this.state_id=state_id;
        _name.clear();
        _id.clear();
        _body.clear();
        _img.clear();
        _imgs.clear();
        _price.clear();
        _color.clear();
        _size.clear();
        _shenas.clear();
        _time.clear();
        _expire.clear();
        _visit_today.clear();
        _visit_total.clear();
        _mobile.clear();
        _cat.clear();
        _user_id.clear();
        _menu_order.clear();
        _link.clear();


    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        //swipeContainer.setRefreshing(false);
        agahi_recycler.setVisibility(View.GONE);

    }

    @Override
    protected String doInBackground(String... strings) {


            try {
                String data = URLEncoder.encode("get_post", "UTF-8") + "=" + URLEncoder.encode("true", "UTF-8");
                //  data+="&"+ URLEncoder.encode("state_id", "UTF-8")+"="+URLEncoder.encode(state_id,"UTF-8");
                data += "&" + URLEncoder.encode("lim", "UTF-8") + "=" + URLEncoder.encode(lim, "UTF-8");


                //
                URL url = new URL(MainActivity.url + "post.php");
                URLConnection connect = url.openConnection();
                connect.setDoOutput(true);
                OutputStreamWriter wr = new OutputStreamWriter(connect.getOutputStream());
                wr.write(data);
                wr.flush();

                //
                InputStreamReader in = new InputStreamReader(connect.getInputStream());
                BufferedReader reader = new BufferedReader(in);
                String line = "";
                StringBuilder sb = new StringBuilder();
                while ((line = reader.readLine()) != null) {
                    sb.append(line);

                }
                return sb.toString();


            } catch (Exception e) {
                Toast.makeText(c, "error in server", Toast.LENGTH_SHORT).show();
                return "er";
            }


    

    }



    @Override
    protected void onPostExecute(String s) {
        super.onPostExecute(s);

        // rotat1.stop();
        //swipeContainer.setRefreshing(false);
        swipeContainer.post(new Runnable() {
            @Override
            public void run() {
                swipeContainer.setRefreshing(false);
            }
        });
        agahi_recycler.setVisibility(View.VISIBLE);
        swipeContainer.setVisibility(View.VISIBLE);
        JSONArray arr=null;
        JSONObject ob=null;

        // Toast.makeText(c,s,Toast.LENGTH_SHORT).show();
        try{
            arr=new JSONArray(s);
            for(int i=0;i<arr.length();i++){

                ob=arr.getJSONObject(i);

                _name.add(ob.getString("title"));
                _id.add(ob.getString("id"));
                _body.add(ob.getString("content"));
                _img.add(ob.getString("img"));
                _imgs.add(ob.getString("imgs"));
                _price.add(ob.getString("price"));
                _color.add(ob.getString("color"));
                _size.add(ob.getString("size"));
                _shenas.add(ob.getString("shenas"));
                _time.add(ob.getString("time"));
                _expire.add(ob.getString("expire"));
                _visit_today.add(ob.getString("todayvisit"));
                _visit_total.add(ob.getString("totalvisit"));
                _mobile.add(ob.getString("mobile"));
                _cat.add(ob.getString("cat"));
                _user_id.add(ob.getString("user"));
                _menu_order.add(ob.getString("order"));
                _link.add(ob.getString("link"));



            }
            final  AgahiRecyclerAdapter adapter=new

                    AgahiRecyclerAdapter(getActivity().getApplicationContext(), getActivity()
                    ,_name
                    ,_id,
                    _cat,
                    _body
                    , _img,
                    _imgs,
                    _price,
                    _size,
                    _color,
                    _mobile,
                    _visit_today,
                    _visit_total
                    ,_expire
                    ,_shenas
                    ,_time
                    ,_menu_order
                    ,_user_id
                    ,_link

            );

            agahi_recycler.setAdapter(adapter);



            Display display = getActivity().getWindowManager().getDefaultDisplay();
            DisplayMetrics outMetrics = new DisplayMetrics();
            display.getMetrics(outMetrics);

            float density  = getResources().getDisplayMetrics().density;
            float dpWidth  = outMetrics.widthPixels / density;
            int columns = Math.round(dpWidth/300);
            final GridLayoutManager mLayoutManager = new GridLayoutManager(getActivity(),columns);
            agahi_recycler.setLayoutManager(mLayoutManager);

            agahi_recycler.setOnScrollListener(new RecyclerView.OnScrollListener() {
                @Override
                public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                    super.onScrolled(recyclerView, dx, dy);
                    if (dy < 0) {
                        rotat2.stop();
                    //    mTask.cancel(true);


                    }
                }

                @Override
                public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
                    int totalItemCount = mLayoutManager.getItemCount();
                    int lastVisibleItem = mLayoutManager.findLastVisibleItemPosition();

                    if (totalItemCount > 1) {
                        if (lastVisibleItem >= totalItemCount - 1) {
                            // End has been reached
                            // do something
                            limit += 6;

                            if (limit < total && scroll == 0 && !rotat2.isStart()) {

                                scroll = 1;


                                mTask = new home_agahi3_server(getActivity().getApplicationContext(), getActivity(),
                                        limit + "", adapter
                                );
                                mTask.executeOnExecutor(mTask.THREAD_POOL_EXECUTOR, "");

                            }


                        } else {

                        }
                    }
                }
            });






        }catch (Exception e){
            //Toast.makeText(c,"errors in json",Toast.LENGTH_SHORT).show();
        }

    }

}