在没有用viewHolder的情况下，listView表现效率低下。如果加载的数量过多则会一点点的消耗内存，直到抛出oom。开始异步加载图片会出现图片错位的问题，后来查阅资料将holder里边的图片地址和图片一一对应起来，在异步加载的回调函数中将其替换回来。
holder.thumb_p_w_picpath.setTag(hotel.getHotelTitlePic()); //避免图标错位，在异步加载成功后替换回来
ImageView p_w_picpathView = (ImageView) listView.findViewWithTag(p_w_picpathUrl);
if(p_w_picpathView != null){ p_w_picpathView.setImageDrawable(p_w_picpathDrawable); p_w_picpathView.setTag(""); }以上关键代码解决图片错位问题。下面是getView()方法
public View getView(int position, View rowView, ViewGroup parent){
final MHotelInfo hotel = this.getItem(position);if (rowView == null) { holder = new ViewHolder();LayoutInflater inflater = ((Activity) this.getContext()).getLayoutInflater();rowView = inflater.inflate(R.layout.hotel_item_view, null);holder.typeName = (TextView) rowView.findViewById(R.id.hotelType)； holder.thumb_p_w_picpath=(ImageView)rowView.findViewById(R.id.img);// 缩略图 holder.distance = (TextView) rowView.findViewById(R.id.distance); rowView.setTag(holder);}else{ holder = (ViewHolder) rowView.getTag();} // 设置ListView的相关值 holder.thumb_p_w_picpath.setTag(hotel.getHotelTitlePic()); //避免图标错位，在异步加载成功后替换回来 holder.typeName.setText(hotel.getTypeName()); if(null == hotel.getHotelTitlePic() || hotel.getHotelTitlePic().equals("")){ //如果没有图标就显示默认图标 holder.thumb_p_w_picpath.setImageResource(R.drawable.downloadfalse); }else{ //异步加载图片 p_w_picpathLoader.loadDrawable(hotel.getHotelTitlePic(), new ImageCallback() { public void p_w_picpathLoaded(Drawable p_w_picpathDrawable, String p_w_picpathUrl) { ImageView p_w_picpathView = (ImageView) listView.findViewWithTag(p_w_picpathUrl); if(p_w_picpathView != null){ p_w_picpathView.setImageDrawable(p_w_picpathDrawable); p_w_picpathView.setTag(""); } } }); }return rowView;}static class ViewHolder { TextView typeName; ImageView thumb_p_w_picpath; }