查询数据库的图片并且按照相册分组,其中包括全部图片

public static class BucketInfo{//一个相册对象
        public int bucket_id;
        public String bucket_display_name;
        public String thumb_data;
        public int count;
        public List<PhotoInfo> innerItem;
}
    public static List<BucketInfo> test(ContentResolver cr) {
        List<BucketInfo> list = new ArrayList<BucketInfo>();
        Cursor cs = cr.query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
                new String[]{"_data", "date_added", "_id", "bucket_id",
                        "bucket_display_name"}, MediaStore.Images.Media.MIME_TYPE + " like ?",
                new String[]{"image/%"}, "date_added DESC");
        if (cs == null) {
            try {
                cs.close();
            } catch (Exception e) {
            }
            return list;
        }
        int count = cs.getCount();
        HashMap<Integer, BucketInfo> hmap = new HashMap<Integer, BucketInfo>();
        cs.moveToFirst();
        //all photos 
        BucketInfo bucketinfo_allPhotos = new BucketInfo();
        bucketinfo_allPhotos.bucket_display_name = GalleryDataServer.ALL_PHOTO_BUCKET_NAME;
        bucketinfo_allPhotos.bucket_id = GalleryDataServer.ALL_PHOTO_BUCKET_ID;
        bucketinfo_allPhotos.innerItem = new ArrayList<PhotoInfo>();
        bucketinfo_allPhotos.count = count;

        for (int i = 0; i < count; i++) {
            PhotoInfo photoInfo = new PhotoInfo();
            String data = cs.getString(0);
            photoInfo._data = data;
            long time = cs.getLong(1);
            photoInfo.date_added = time;
            int _id = cs.getInt(2);
            photoInfo._id = _id;

            int bucketid = cs.getInt(3);
            String bucketname = cs.getString(4);

            if (!hmap.containsKey(bucketid)) {
                BucketInfo bucketInfo = new BucketInfo();
                bucketInfo.bucket_display_name = bucketname;
                bucketInfo.bucket_id = bucketid;
                bucketInfo.thumb_data = data;
                bucketInfo.innerItem = new ArrayList<PhotoInfo>();
                bucketInfo.innerItem.add(photoInfo);
                bucketInfo.count = bucketInfo.innerItem.size();
                hmap.put(bucketid, bucketInfo);
                list.add(bucketInfo);
            } else {
                BucketInfo bucketInfo = hmap.remove(bucketid);
                int index = 0;
                if (list.contains(bucketInfo)) {
                    index = list.indexOf(bucketInfo);
                    list.remove(index);
                }
                bucketInfo.bucket_display_name = bucketname;
                bucketInfo.bucket_id = bucketid;
                bucketInfo.innerItem.add(photoInfo);
                bucketInfo.count = bucketInfo.innerItem.size();
                hmap.put(bucketid, bucketInfo);
                list.add(index, bucketInfo);
            }
            if(TextUtils.isEmpty(bucketinfo_allPhotos.thumb_data)){
                bucketinfo_allPhotos.thumb_data = data;
            }
            bucketinfo_allPhotos.innerItem.add(photoInfo);
            // String str = try_new SimpleDateFormat("yyyy-MM-dd").format(try_new Date(
            // time * 1000));
            cs.moveToNext();
        }
        try {
            cs.close();
        } catch (Exception e) {
        }
        list.add(0,bucketinfo_allPhotos);
        return list;
    }

2.将相册相同日期的分成一组

之前通过SimpleFormat转成yyyy-MM-dd 判断是否是同一天,在照片很多的时候,非常耗时,后面直接通过比较时间戳,效率大大的提高

    public static final int SECONDS_IN_DAY = 60 * 60 * 24;
    public static final long MILLIS_IN_DAY = 1000L * SECONDS_IN_DAY;
    public static boolean isSameDayOfMillis(final long ms1, final long ms2) {
        final long interval = ms1 - ms2;
        return interval < MILLIS_IN_DAY
                && interval > -1L * MILLIS_IN_DAY
                && toDay(ms1*1000) == toDay(ms2*1000);
    }
    private static long toDay(long millis) {
        return (millis + TimeZone.getDefault().getOffset(millis)) / MILLIS_IN_DAY;
    }
    public static ArrayList<ArrayList<PhotoInfo>> SplitPhotoInfoListByDate(List<PhotoInfo> itemList) {
        ArrayList<ArrayList<PhotoInfo>> splitedList = new ArrayList<ArrayList<PhotoInfo>>();
        ArrayList<PhotoInfo> oneDayPhotoList = new ArrayList<PhotoInfo>();
        long date=0;
        int splitedListIndex = -1;
        for (int i = 0; i < itemList.size(); i++) {
            long strDate = itemList.get(i).date_added;
            if (!isSameDayOfMillis(date,strDate)) {
                splitedListIndex++;
                date = strDate;
                oneDayPhotoList = new ArrayList<PhotoInfo>();
                splitedList.add(oneDayPhotoList);
            }
            splitedList.get(splitedListIndex).add(itemList.get(i));
        }
        return splitedList;
    }

3.手动加入日期着一个属性分类

本方法多做一件事,拆分得更细致,每一行一行都分出来的,4代表的是一行4列,这样是因为我使用的RecyclerView 嵌套的方法,内部Recyclerview高度写死,导致Recyclerview复用失效,导致卡顿,所以每一行是一个数据组,而不是每一天的数据是一个数据组

 public static ArrayList<ArrayList<PhotoInfo>> FormatePhotoInfoListFromSplitedListForAdapter(ArrayList<ArrayList<PhotoInfo>> splitedList) {
        ArrayList<ArrayList<PhotoInfo>> formatedList = new ArrayList<ArrayList<PhotoInfo>>();

        for (int i = 0; i < splitedList.size(); i++) {
            ArrayList<PhotoInfo> photoInfosInOneDay = splitedList.get(i);

            ArrayList<PhotoInfo> dataItem = new ArrayList<PhotoInfo>();
            dataItem.add(new PhotoDateInfo(photoInfosInOneDay.get(0).date_added));
            formatedList.add(dataItem);

            for (int j = 0; (j * 4) < photoInfosInOneDay.size(); j++) {
                int photoInOneDayIndex = 0;
                ArrayList<PhotoInfo> photoLineItem = new ArrayList<PhotoInfo>();
                for (int k = 0; k < 4; k++) {
                    photoInOneDayIndex = j * 4 + k;
                    if (photoInOneDayIndex < photoInfosInOneDay.size()) {
                        photoLineItem.add(photoInfosInOneDay.get(photoInOneDayIndex));
                    } else {
                        break;
                    }
                }

                formatedList.add(photoLineItem);
            }
        }

        return formatedList;
    }