Trying accessing and setting image from a class that is not implementing it xml

Hi everybody i have a listview that contains all the contacts of my phone am trying in my xml file to set a image to all of them and trying to set invisible the ones that i don't need to appear i have this :

    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    listView = (ListView) findViewById(R.id.list);
    img = (ImageView)findViewById(R.id.img);

    Cursor phones = getContentResolver().query(
            ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null, null,null, null);

    while (phones.moveToNext()){
        String name = phones
                .getString(phones
                        .getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));

        String phoneNumber = phones
                .getString(phones
                        .getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));

        ContactBean objContact = new ContactBean();
        objContact.setName(name);
        objContact.setPhoneNo(phoneNumber);         //
        list.add(objContact);

    }
    phones.close();


        for (int i = 0; i < SQLiteCrudEmc2.Emc2Contacts.length; i++) {

            if(!test(SQLiteCrudEmc2.Emc2Contacts[i].toString()) ){
                img = (ImageView)findViewById(R.id.img);
                     Log.i("eeeeeeee",SQLiteCrudEmc2.Emc2Contacts[i].toString() );
                Toast.makeText(ContactListActivity.this, "Numéro retrouvé", Toast.LENGTH_LONG).show();
                 img.setVisibility(View.INVISIBLE);// My problem here
            }
        }


    ContanctAdapter objAdapter = new ContanctAdapter(
            ContactListActivity.this, R.layout.alluser_row,list);
    listView.setAdapter(objAdapter);

    if (null != list && list.size() != 0) {
        Collections.sort(list, new Comparator<ContactBean>() {

            @Override
            public int compare(ContactBean lhs, ContactBean rhs) {
                return lhs.getName().compareTo(rhs.getName());
            }
        });

        AlertDialog alert = new AlertDialog.Builder(
                ContactListActivity.this).create();
        alert.setTitle("");


    } else {
        showToast("No Contact Found!!!");
    }
}

My contats adapter here :

public class ContanctAdapter extends ArrayAdapter<ContactBean> {

private Activity activity;
private List<ContactBean> items;
private int row;
private ContactBean objBean;
ImageView img;

ViewHolder holder;
public ContanctAdapter(Activity act, int row, List<ContactBean> items) {
    super(act, row, items);

    this.activity = act;
    this.row = row;
    this.items = items;
}

@SuppressWarnings("null")
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
    View view = convertView;
    if (view == null){
        LayoutInflater inflater = (LayoutInflater) activity
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        view = inflater.inflate(row, null);

        holder = new ViewHolder();
        view.setTag(holder);

    } else {
        holder = (ViewHolder) view.getTag();
    }

    if ((items == null)||((position + 1) > items.size()))
        return view;

    objBean = items.get(position);

    holder.tvname = (TextView) view.findViewById(R.id.tvname);
    holder.tvPhoneNo = (TextView) view.findViewById(R.id.tvphone);
    holder.img = (ImageView)view.findViewById(R.id.img);
    if (holder.tvname != null && null != objBean.getName()
            && objBean.getName().trim().length() > 0) {
        holder.tvname.setText(Html.fromHtml(objBean.getName()));
    }
    if (holder.tvPhoneNo != null && null != objBean.getPhoneNo()
            && objBean.getPhoneNo().trim().length() > 0) {
        holder.tvPhoneNo.setText(Html.fromHtml(objBean.getPhoneNo()));
    }

    return view;
}



public class ViewHolder {
    public TextView tvname, tvPhoneNo;
    ImageView img;

}
public class IsInMyContactsList extends Activity {
    public IsInMyContactsList(){

    }

    public  Boolean test(String num){

        Boolean isOk = false;
        Cursor phone1 = getContentResolver().query(
                ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null, null,null, null);

        while (phone1.moveToNext()){

            String phoneNumber = phone1
                    .getString(phone1  
                            .getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
            if(num.equals(phoneNumber)) 

                isOk = true;

    }
        phone1.close();


        return isOk;

    }

}

}

i have a Java.lang.NullPointerExeption please help.