无法在折线图中显示总和数据的正确结果

Question

我尝试从 JSON 中获取数据，JSON 结构如下

{"count" : 5,"result" : [
{"id": 1,
        "date_invoice": "2022-03-25",
        "state": "paid",
        "amount_untaxed": 25000
    },
{"id": 2,
        "date_invoice": "2022-03-26",
        "state": "paid",
        "amount_untaxed": 161500
    },
{"id": 3,
        "date_invoice": "2022-03-27",
        "state": "paid",
        "amount_untaxed": 25000
    },
{"id": 4,
        "date_invoice": "2022-03-30",
        "state": "paid",
        "amount_untaxed": 165000
    },
{"id": 5,
        "date_invoice": "2022-03-30",
        "state": "paid",
        "amount_untaxed": 70000
    }
]}

我已经可以获取 json 数据并将其显示为折线图，我使用 mpchartandroid 库来显示我的图表。我的问题是，当某些数据具有相同日期时，我无法显示总和数据 amount_untaxed 的结果。这是我的 sum

代码

            detail = new HashMap<>();
            detail = new Gson().fromJson(_response, new TypeToken<HashMap<String, Object>>(){}.getType());
            str= (new Gson()).toJson(detail.get("result"), new TypeToken<ArrayList<HashMap<String, Object>>>(){}.getType());
            listmap_detail = new Gson().fromJson(str, new TypeToken<ArrayList<HashMap<String, Object>>>(){}.getType());
            listmap_Item = listmap_detail;
            price_subtotal = Float.valueOf(0);
            for (int i=0;i<listmap_detail.toArray().length;i++){
                dateString = listmap_detail.get(i).get("date_invoice").toString().replace("-","");
                format1 = new SimpleDateFormat("yyyyMMdd");
                format1.setTimeZone(TimeZone.getTimeZone("GMT+7"));
                format2 = new SimpleDateFormat("dd");
                SimpleDateFormat format3 = new SimpleDateFormat("MMMM yyyy");
                SimpleDateFormat format4 = new SimpleDateFormat("dd-MM");
                try {
                    today = new Date();
                    current_date = format3.format(today);
                    Date date = format1.parse(dateString);
                    dateFinal = format2.format(date);
                    String dateSementara = format2.format(today);

                    if (dateSementara.equals(dateFinal)){
                        price_subtotal += Float.valueOf(listmap_detail.get(i).get("amount_untaxed").toString());
                    }
                    line_entries.add(new Entry(Float.parseFloat(dateFinal),price_subtotal));
                }
                catch (Exception e){

                }
            }

我的图表

有什么办法可以解决吗？

Answer 1

我不确定您为什么按月中的某天绘制此图（如果数据集跨越多个月，这将中断）但下面的代码适用于您提供的案例。

它首先按日期收集要绘制到 HashMap 中的数据，如果在给定日期有多个条目，则对值求和，然后将该映射转换为图表的 x-y 个条目。

// no need to call Gson multiple times - once you have 
// parsed it you can just get the entries from the map
HashMap<String,Object> detail = new Gson().fromJson(jsonStr, new TypeToken<HashMap<String, Object>>(){}.getType());
List<Map<String,Object>> listmap_detail = (List<Map<String, Object>>) detail.get("result");

// Collect values per day into a map first to handle 
// summing duplicate values
Map<String,Float> daily_sum = new HashMap<>();
for(Map<String,Object> entry : listmap_detail) {
    String date = (String) entry.get("date_invoice");
    Float amt = ((Double) entry.get("amount_untaxed")).floatValue();
    if( !daily_sum.containsKey(date) ) {
        daily_sum.put(date, amt);
    }
    else {
        daily_sum.put(date, amt + daily_sum.get(date));
    }
}

// Print statements are your friend when it comes to 
// debugging code like this
System.out.println("DEBUG: daily sum = " + daily_sum);

// Sort the dates so the data is in chronological order
List<String> keys = new ArrayList<>(daily_sum.keySet());
Collections.sort(keys);

SimpleDateFormat isoFormat = new SimpleDateFormat("yyyy-MM-dd");
SimpleDateFormat dayOfMonthFormat = new SimpleDateFormat("dd");

// WARNING: MPAndroidChart requires entries to be ordered by x value - if your 
// data set spans multiple months this will cause a problem 
// below since the data will not be in order by day of month.
// Adjust for your use case as-needed.
for(String isoDate : keys) {
    try {
        Date date = isoFormat.parse(isoDate);
        float dayOfMonth = Float.parseFloat(dayOfMonthFormat.format(date));
        Float dailyAmt = daily_sum.get(isoDate);
        System.out.println("DEBUG: plotting " + dayOfMonth + "," + dailyAmt);
        line_entries.add(new Entry(dayOfMonth,dailyAmt));
    } catch (ParseException e) {
        e.printStackTrace();
    }
}

无法在折线图中显示总和数据的正确结果

Cannot display right result of sum data in line graph

charts

android

json

if-statement