发现Tag在View中还是很有作用的属性，API中这样描述的：
Tags
Unlike IDs, tags are not used to identify views. Tags are essentially an extra piece of information that can be associated with a view. They are most often used as a convenience to store data related to views in the views themselves rather than by putting them in a separate structure.
Tag不像ID是用标示view的。Tag从本质上来讲是就是相关联的view的额外的信息。它们经常用来存储一些view的数据，这样做非常方便而不用存入另外的单独结构。
下面这个例子是从eoe中看到的，给我很大启发：
public class FileListAdapter extends BaseAdapter {
private LayoutInflater mInflater;
private Bitmap mIcon_folder;
private Bitmap mIcon_file;
private Bitmap mIcon_image;
private Bitmap mIcon_audio;
private Bitmap mIcon_video;
private Bitmap mIcon_apk;
private List<String> items;
private List<String> paths;
private List<String> sizes;
private int isZoom = 0;
// MyAdapter的构造器
public FileListAdapter(Context context, List<String> it, List<String> pa,
List<String> si, int zm) {
mInflater = LayoutInflater.from(context);
items = it;
paths = pa;
sizes = si;
isZoom = zm;
mIcon_folder = BitmapFactory.decodeResource(context.getResources(),
R.drawable.folder); // 文件夹的图标
mIcon_file = BitmapFactory.decodeResource(context.getResources(),
R.drawable.file); // 文件的图文件
mIcon_image = BitmapFactory.decodeResource(context.getResources(),
R.drawable.image); // 图片的图文件
mIcon_audio = BitmapFactory.decodeResource(context.getResources(),
R.drawable.audio); // 音频的图文件
mIcon_video = BitmapFactory.decodeResource(context.getResources(),
R.drawable.video); // 视频的图文件
mIcon_apk = BitmapFactory.decodeResource(context.getResources(),
R.drawable.apk); // apk文件
}
@Override
public int getCount() {
return items.size();
}
@Override
public Object getItem(int position) {
return items.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup par) {
Bitmap bitMap = null;
ViewHolder holder = null;
if (convertView == null) {
// 使用自定义的list_items作为Layout
convertView = mInflater.inflate(R.layout.file_list_items, null);
// 初始化holder的text与icon
holder = new ViewHolder();
holder.f_title = ((TextView) convertView.findViewById(R.id.f_title));
holder.f_text = ((TextView) convertView.findViewById(R.id.f_text));
holder.f_icon = ((ImageView) convertView.findViewById(R.id.f_icon));
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
File f = new File(paths.get(position).toString());
// 设置文件或文件夹的文字与icon
holder.f_title.setText(f.getName());
String f_type = MyUtil.getMIMEType(f, false);
if (f.isDirectory()) {
holder.f_icon.setImageBitmap(mIcon_folder);
holder.f_text.setText("");
} else {
holder.f_text.setText(sizes.get(position));
if ("image".equals(f_type)) {
if (isZoom == 1) {
bitMap = MyUtil.fitSizePic(f);
if (bitMap != null) {
holder.f_icon.setImageBitmap(bitMap);
} else {
holder.f_icon.setImageBitmap(mIcon_image);
}
} else {
holder.f_icon.setImageBitmap(mIcon_image);
}
bitMap = null;
} else if ("audio".equals(f_type)) {
holder.f_icon.setImageBitmap(mIcon_audio);
} else if ("video".equals(f_type)) {
holder.f_icon.setImageBitmap(mIcon_video);
} else if ("apk".equals(f_type)) {
holder.f_icon.setImageBitmap(mIcon_apk);
} else {
holder.f_icon.setImageBitmap(mIcon_file);
}
}
return convertView;
}
/**
* 不单独写get set可以提高效率 class ViewHolder
* */
private class ViewHolder {
TextView f_title;
TextView f_text;
ImageView f_icon;
}
}