Unable to decode stream: java.io.FileNotFoundException

无法通过SimpleAdapter适配器加载网络图片，只能通过添加内部类的形式

listAdapter.setViewBinder(new ViewBinder() {
                    @Override
                    public boolean setViewValue(View view, Object attentionList, String textRepresentation) {
                            // TODO Auto-generated method stub
                            if(view instanceof ImageView && attentionList instanceof Bitmap){
                                    ImageView iv=(ImageView)view;
                                    iv.setImageBitmap((Bitmap) attentionList);
                                    return true;
                            }else{
                                    return false;
                            }	
                    }
            });