@Override
public View getView(int position, View convertView, ViewGroup parent) {
    ViewHolder holder;
    if(convertView == null) {
        convertView = LayoutInflater.from(mContext).inflate(R.layout.user_layout_item, null);

        holder = new ViewHolder();
        holder.userImageView = (ImageView) convertView.findViewById(R.id.userImageView);
        holder.nameLabel = (TextView) convertView.findViewById(R.id.nameLabel);
        convertView.setTag(holder);
    }else{
        holder = (ViewHolder) convertView.getTag();
    }
    ParseUser user = mUsers.get(position);
    if(ParseFacebookUtils.isLinked(user)) {
        String facebookId = user.getString(ParseConstants.KEY_FACEBOOK_ID);
        String facebookProfilePicUrl = "https://graph.facebook.com/"
                + facebookId + "/picture";
        Picasso.with(mContext)
                .load(facebookProfilePicUrl)
                .into(holder.userImageView);
        holder.nameLabel.setText(user.getString(ParseConstants.KEY_UNIQUE_USERNAME));
    }
    return convertView;
}

public static class ViewHolder{
    ImageView userImageView;
    TextView nameLabel;

}