Android : Android: ListView - ListItem Button and Text Change Effecting Other ListItems

Here is my list view adapter

    public class MyArrayAdapter extends ArrayAdapter<MyDataModel> {

        Context mContext;
        LayoutInflater mInflater;
        Set<Integer> complete;


        public MyArrayAdapter(Context context, int resource, List<MyDataModel> activityList) {
            super(context, resource, activityList);
            mContext = context;
            mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            complete = new HashSet<Integer>();
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            View view = convertView;
            final Holder holder;
            if(view==null)
            {
                view = mInflater.inflate(R.layout.activity_list_item, parent, false);
                holder = new Holder();
                holder.heading= (TextView)view.findViewById(R.id.heading);
                holder.quantity = (EditText)view.findViewById(R.id.quantity);
                holder.category = (TextView)view.findViewById(R.id.category);
                holder.time = (TextView)view.findViewById(R.id.time);
                holder.circle = (ImageView)view.findViewById(R.id.circle);
                view.setTag(holder);
            }
            else
            {
                holder = (Holder) view.getTag();
            }
            final int pos = position; 
            if(complete.contains(pos))
            {
                holder.circle.setImageResource(R.drawable.check_mark);
                holder.heading.setPaintFlags(holder.heading.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
                holder.category.setPaintFlags(holder.category.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
                holder.time.setVisibility(View.GONE);
                holder.circle.setFocusable(false);
                holder.circle.setClickable(false);
                return view;
            }
            else
            {
                try
                {
                    final MyDataModel h = getItem(position);
                    /...get my required values from the model above..
                    holder.heading.setText(heading);
                    holder.category.setText(category);
                    holder.time.setText(time);
                    holder.circle.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                                NetworkCallAsync async = new NetworkCallAsync(param,h.getScheduledEventId().toString(),"Y",param,
                                        holder.heading,holder.category,holder.quantity,holder.circle,holder.time, pos, holder.holderComplete);
                                async.execute();
                        }
                    });

                }
                catch(Exception e)
                {
                    e.printStackTrace();
                }
            }

            return view;
        }



        private static final class Holder 
        {
            public ImageView circle;
            public TextView heading;
            public EditText quantity; 
            public TextView time;
            public TextView category;
        }

        class NetworkCallAsync extends AsyncTask<String,String,String>
        {
            ....
//all init variables here 



            public NetworkCallAsync(Integer p1, String p2,Stringp3, String p4,
                    TextView heading,TextView category, EditText quantity, ImageView circle, TextView time, final int pos)
            {
                ..
                ...
                .....
                .....
                this.heading = heading;
                this.quantity = quantity;
                this.circle = circle;
                this.time = time;
                this.category = category;
                this.pos = pos;

            }

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

                //do a network call here and after a sucess , below happens 
                .............
                return "success";
            }

                    @Override
                    protected void onPostExecute(String result) {
                        super.onPostExecute(result);
                        if(result.equals("success"))
                        {
            //make UI updates
                            circle.setImageResource(R.drawable.check_mark);
                            heading.setPaintFlags(heading.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
                            category.setPaintFlags(category.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
                            time.setVisibility(View.GONE);
                            complete.add(pos);
                            notifyDataSetChanged();
                        }
                        }

        }
    }

To just shorted it up for you reader, upon a click of an image view inside a list item (or when I check it), I am popping up an Async Task ( a really short network call) and if I get a succesful result, I make UI updateds for that particluar list item and strike off the text in the list item, please see my onPostExecute(). At that point i store the position in a HashSet and in getView(....) check if position is contained, and if contained then display that the particluar list item has already been checked. But the issue is , even other rows are getting effected, despite this. Is there any way else ? Please help me out.