滚动时GridView将消失

Question

当我向上和向下滚动GridView时，gridview将开始失去其子项，并且最终（间歇性地）如果我做了太多滚动，整个gridview将在页面底部消失。

这是我的适配器代码：

public class Adapter extends BaseAdapter {

    private Context context;
    private LayoutInflater inflater;
    private List<Item> list;

    public Adapter(Context _context, List<Item> _list){
        this.context = _context;
        this.list = _list;
        this.inflater = LayoutInflater.from(context);
    }

    @Override
    public int getCount() {
        return this.list.size() - 1;
    }

    @Override
    public Object getItem(int position) {
        return this.list.get(position);
    }

    @Override
    public long getItemId(int arg0) {
        return 0;
    }

    public class ViewHolder {
        ImageView imageView;
        TextView itemLabel;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;

        if (convertView == null) {
            convertView = View.inflate(context, .., null);
            holder = new ViewHolder();
            holder.imageView = (ImageView)convertView.findViewById(..);
            holder.itemLabel = (TextView)convertView.findViewById(..);
            convertView.setTag(holder);
        } else {
           holder = (ViewHolder) convertView.getTag();
        }

        Item item = list.get(position + 1);
        holder.itemLabel.setText(item.getTitle());
        holder.imageView.setImageDrawable(item.getImage());

        return convertView;
    }
}

可能有什么问题，因为我的适配器是标准适配器？