android下对于Cursor的中文拼音排序实现

android下面需要对数据库某列的内容,按照中文拼音的顺序来排序。
baidu了下，发现常见的方式是要在数据库增加一列来存放拼音，专门用该列来排序，比如联系人就是用此方式实现的。
换google,发现有邮件中说,可以实现CursorWrapper,来达到排序功能。
具体看 How to do sorting on cursor?
http://groups.google.com/group/android-developers/browse_thread/thread/f1fc3e0fc87a3fc6

主要思路是:override move系列的方法,让cursor以自己想要的顺序来移动,从而达到对cursor排序的目的。
比如数组A0里有 4(0),3(1),1(2),2(3),括号内为位置,排序后用数据记录A1:1(2),2(3),3(1),4(0)
要访问第一个元素,则访问A1[0]得到1(2),根据(2)找到在A0中的实际位置2,即1(2)

参考了下系统的CursorWrapper和AbstractCursor代码实现,另外有时间可以顺带了解下MatrixCursor

直接上代码

import java.text.Collator;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;

import android.database.Cursor;
import android.database.CursorWrapper;

public class SortCursor extends CursorWrapper{
	Cursor mCursor;
	ArrayList<SortEntry> sortList = new ArrayList<SortEntry>();
	int mPos = 0;
	
	public class SortEntry {
		public String key;
		public int order;
	}
	
	//直接初始化,加快比较速度,在G3上从3s->0.2s
	@SuppressWarnings("rawtypes")
	private Comparator cmp = Collator.getInstance(java.util.Locale.CHINA);
	
	@SuppressWarnings("unchecked")	
	public Comparator<SortEntry> comparator = new Comparator<SortEntry>(){		
		@Override
		public int compare(SortEntry entry1, SortEntry entry2) {			
			return cmp.compare(entry1.key, entry2.key);       
		}	
	};

	public SortCursor(Cursor cursor,String columnName) {		
		super(cursor);
		MusicLog.i("MediaScanner", "start-----------");
		// TODO Auto-generated constructor stub
		mCursor = cursor;
		if(mCursor != null && mCursor.getCount() > 0) {
			int i = 0;
			int column = cursor.getColumnIndexOrThrow(columnName);
			for(mCursor.moveToFirst();!mCursor.isAfterLast();mCursor.moveToNext(),i++){
				SortEntry sortKey = new SortEntry();
				sortKey.key = cursor.getString(column);
				sortKey.order = i;
				sortList.add(sortKey);
			}
		}
		MusicLog.i("MediaScanner", "start1-----------");
		//排序
		Collections.sort(sortList,comparator);
		MusicLog.i("MediaScanner", "start2-----------");
	}
	
    public boolean moveToPosition(int position)
    {
    	if(position >= 0 && position < sortList.size()){
    		mPos = position;
    		int order = sortList.get(position).order;
    		return mCursor.moveToPosition(order);
    	}
    	if(position < 0){
    		mPos = -1;
    	}
    	if(position >= sortList.size()){
    		mPos = sortList.size();
    	}
    	return mCursor.moveToPosition(position);        
    }
    
    public boolean moveToFirst() {    	
        return moveToPosition(0);
    }
    
    public boolean moveToLast(){
    	return moveToPosition(getCount() - 1);
    }
    
    public boolean moveToNext() {    	    	
        return moveToPosition(mPos+1);
    }
    
    public boolean moveToPrevious() {    	
        return moveToPosition(mPos-1);
    }
	
    public boolean move(int offset) {    	
        return moveToPosition(mPos + offset);
    }
    
    public int getPosition() {    	
    	return mPos;
    }
}

参考文章
Android 对汉字字符串按照拼音排序
http://hi.baidu.com/luyanlong1/blog/item/2c31b51d938b79ecae5133fc.html
The Busy Coder's Guide to Android Development 这本书应该也不错,推荐下