//想要的返回值所在的列            String[] projection = { MediaStore.Images.Thumbnails._ID};            //图片信息存储在 android.provider.MediaStore.Images.Thumbnails数据库             //快速查询数据库中的图片对应存放路劲                     Cursor cursor = managedQuery(                    MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI,                    projection, //List of columns to return ：想要他返回的列                    null, // Return all rows                    null,                    null);            int columnIndex = cursor.getColumnIndexOrThrow(MediaStore.Images.Thumbnails._ID);            uriArray = new Uri[cursor.getCount()];//把图片路径放在数组中

    while(cursor.moveToNext()&&i<cursor.getCount())            {   //移到指定的位置，遍历数据库                cursor.moveToPosition(i);                uri = Uri.withAppendedPath(MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI,cursor.getInt(columnIndex)+"");                uriArray[i]=uri;                try {                    bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(uri));                    if (bitmap != null) {                        //将原来的位图转换成新的位图                        newBitmap = Bitmap.createScaledBitmap(bitmap,80, 80,true);                        bitmap.recycle();//释放内存                        if (newBitmap != null) {                            publishProgress(new LoadedImage(newBitmap));                        }                    }                } catch (IOException e) {}                i++;            }