从Parse.com下载照片

Question

我在Parse.com下载Photo时遇到问题。 在Parse我有6张照片，但在我将它下载到我的照片数组列表后，我显示photos.size（）= 12.我不明白为什么它是照片的两倍？我该如何解决？

try {
        ParseQuery <ParseObject> query = new ParseQuery <> ("photo");
        query.orderByAscending("ImageName");
        List <ParseObject> listA = query.find();
        for (final ParseObject mPhoto: listA) {
            final Photo newPhoto = new Photo();
            final ParseFile photo = (ParseFile) mPhoto.get("imageFile");
            photo.getDataInBackground(new GetDataCallback() {
                @Override
                public void done(byte[] data, com.parse.ParseException e) {
                    if (e == null) {
                        Bitmap bmp = BitmapFactory.decodeByteArray(data, 0, data.length);
                        newPhoto.setBitmap(bmp);
                        newPhoto.setTrade_id((String) mPhoto.get("trade_id"));
                        photos.add(newPhoto);
                    } else {
                        Log.e("test", "Problem load image the data.");
                    }
                }
            });
        }
    } catch (com.parse.ParseException e) {
        Log.e("Error", e.getMessage());
        e.printStackTrace();
    }


try {
        ParseQuery <ParseObject> query = new ParseQuery < > ("trade");
        query.addDescendingOrder("updatedAt");
        List < ParseObject > listA = query.find();
        for (ParseObject mTrade: listA) {
            Trade newTrade = new Trade();
            newTrade.setUpdateCount((int) mTrade.get("UpCount"));
            newTrade.setmUser((String) mTrade.get("user"));
            newTrade.setmKind((String) mTrade.get("kind"));
            newTrade.setmAddress((String) mTrade.get("address"));
            newTrade.setmCost((String) mTrade.get("cost"));
            newTrade.setmDetail((String) mTrade.get("detail"));
            newTrade.setmID((String) mTrade.get("trade_id"));
            newTrade.setmPhone((String) mTrade.get("phone"));
            newTrade.setmTopic((String) mTrade.get("topic"));
            for (int i = 0 ; i < photos.size() ;i++){
                if (newTrade.getmID().equals(photos.get(i).getTrade_id())){
                    newTrade.addBitmap(photos.get(i).getBitmap());

                }
                if (newTrade.getBitmaps().size()==4){
                    i=photos.size();
                }
            }
            trades.add(newTrade);
        }

    } catch (com.parse.ParseException e) {
        Log.e("Error", e.getMessage());
        e.printStackTrace();
    }