在加载更多数据时，将ProgressBar添加到GridView上的最后一个单元格

Question

我的应用程序基于网格视图，该视图显示来自服务器的许多图像。 我试图不要超载服务器，所以我想一次显示20个图像，当用户向下滚动时，应用程序显示更多图像。 我想在Gridview位于屏幕底部时添加一个额外的单元格，然后在服务器完成加载额外图像时使其为GONE，但我找不到解决方案。这里是来自h＆amp; m应用程序的图片 - 他们设法弄清楚...我正在尝试构建与他们所做的非常相似的东西。 谁能帮我？ 这是我到目前为止的代码.. 谢谢！

public class MyAdapter extends BaseAdapter {
    LayoutInflater inflater;

    private Context mContext;

    // ImageLoader imageLoader;

    public MyAdapter(Context c) {
        mContext = c;
        imageLoader = ImageLoader.getInstance();            
        inflater = (LayoutInflater) mContext
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

    }

    class ViewHolder {
        ProgressBar spinner;
        TextView Price;
        ImageView imageView;
        RelativeLayout Item;
    }

    @Override
    public int getCount() {
        return mThumbIds.length;
    }

    @Override
    public Object getItem(int arg0) {
        return mThumbIds[arg0];
    }

    @Override
    public long getItemId(int arg0) {
        return arg0;
    }

    @Override
    public void notifyDataSetChanged() {
        super.notifyDataSetChanged();
    }

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

        View grid = convertView;
        final ViewHolder holder;

        if (convertView == null) {
            grid = new View(mContext);
            grid = inflater.inflate(R.layout.list_row_catalog, parent,
                    false);
            holder = new ViewHolder();
            holder.spinner = (ProgressBar) grid
                    .findViewById(R.id.progressBar1);
            holder.Price = (TextView) grid.findViewById(R.id.item_text);
            holder.imageView = (ImageView) grid.findViewById(R.id.image);
            holder.Item = (RelativeLayout) grid.findViewById(R.id.itemGrid);
            grid.setTag(holder);

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

        }
    //  SpinnerLoading.setVisibility(View.GONE);
        holder.spinner.setVisibility(View.GONE);
        holder.Price.setText(String.valueOf(TheAdapterPrice[position]));
        imageLoader.displayImage(mThumbIds[position], holder.imageView,
                options, new SimpleImageLoadingListener() {
                    @Override
                    public void onLoadingStarted(String imageUri, View view) {
                        holder.spinner.setVisibility(View.VISIBLE);
                    }

                    @Override
                    public void onLoadingFailed(String imageUri, View view,
                            FailReason failReason) {
                        holder.spinner.setVisibility(View.GONE);
                    }

                    @Override
                    public void onLoadingComplete(String imageUri,
                            View view, Bitmap loadedImage) {
                        holder.spinner.setVisibility(View.GONE);
                    }
                });
        holder.Item.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                gridView.setVisibility(View.GONE);
                BigSpinner.setVisibility(View.VISIBLE);
                Loading.setVisibility(View.VISIBLE);
                Intent intent = new Intent(getActivity(),
                        Catalog_Store.class);
                intent.putExtra("TheItem", mThumbIds[position]);
                intent.putExtra("PriceShirt", TheAdapterPrice[position]);
                // startActivity(intent);

                GetTheIDFromParseServers(intent, TheClassName,
                        mThumbIds[position]);
            }
        });
        TotalItemDisplay = getCount();
        if (continueScrollSelector == true) {
            if (position == TotalItemDisplay - 1) {

                //this method make the call to the server to add images
                AddMoreImages();
                // The ScrollSelector is basically how match pictures to
                // load every time the user
                // scrolls down
                ScrollSelector = ScrollSelector + MorePhotosToLoad;

            } else {

            }
        }
        return grid;
    }