回调接口方法简述
待实现的接口

@Overridepublic View getView( int position, View convertView, ViewGroup parent) {Log.i(TAG, "getView()");if(convertView == null){//获取布局convertView = LayoutInflater.from(cext).inflate(R.layout.item_image, null);//获取布局里面的ImageView组件final ImageView imageView = (ImageView)convertView.findViewById(R.id.item_imageView);//获取当前的图片的url地址final String url = urlList.get(position).getImageUrl();//为图片设置一个tag 这个很重要这样的目的是为了控制每个ImageView组件都显示对应的图片imageView.setTag(url);Log.i(TAG, "初始化"+(position));//开始异步加载图片//[color=red]实例化一个实现接口的对象，供上一段代码loadDrawable调用[/color] Drawable drawable = asyncLoadImage.loadDrawable(url, new AsyncLoadImage.ImageCallback(){@Overridepublic void imageLoad(Drawable image,String imageUrl) {//判断当前的url地址是否为当前组件的url地址 是则加载图片if(imageUrl.equals(imageView.getTag())){   imageView.setImageDrawable(image);}}});}else{Log.i(TAG, "完成后的初始化"+(position));final ImageView imageView = (ImageView)convertView.findViewById(R.id.item_imageView);final String url = urlList.get(position).getImageUrl();imageView.setTag(url); Drawable drawable = asyncLoadImage.loadDrawable(url, new AsyncLoadImage.ImageCallback(){@Overridepublic void imageLoad(Drawable image,String imageUrl) {if(imageUrl.equals(imageView.getTag())){imageView.setImageDrawable(image);}}});}return convertView;}