java - 为什么我的数组未显示为已过滤？

Question

我正在尝试使用此示例按价格从最低到最高对这个 JSON 对象进行 排序 如何在 java 中对 JSON 对象进行排序？. 但是当我尝试显示我的列表时，它似乎没有排序。我不确定我做错了什么，有人能指出我正确的方向。我已经阅读了几篇文章，他们都说要使用集合对 JSON 对象进行排序，我尝试在下面实现它，但它不起作用任何建议都值得赞赏。

json:-

[ {
 "symbol" : "SAN",
  "companyName" : "Banco Santander, S.A.",
  "marketCap" : 62296657920,
  "sector" : "Financial Services",
  "industry" : "Banks—Diversified",
  "beta" : 1.74298500000000000653699316899292171001434326171875,
  "price" : 3.5800000000000000710542735760100185871124267578125,
  "lastAnnualDividend" : 0.24899999999999999911182158029987476766109466552734375,
  "volume" : 4284228,
  "exchange" : "New York Stock Exchange",
  "exchangeShortName" : "NYSE",
  "country" : "ES",
  "isEtf" : false,
  "isActivelyTrading" : true
}, {
  "symbol" : "ABEV",
  "companyName" : "Ambev S.A.",
  "marketCap" : 48729493504,
  "sector" : "Consumer Defensive",
  "industry" : "Beverages—Brewers",
  "beta" : 0.93046200000000001129052407122799195349216461181640625,
  "price" : 3.0099999999999997868371792719699442386627197265625,
  "lastAnnualDividend" : 0.0970000000000000028865798640254070051014423370361328125,
  "volume" : 24947634,
  "exchange" : "New York Stock Exchange",
  "exchangeShortName" : "NYSE",
  "country" : "BR",
  "isEtf" : false,
  "isActivelyTrading" : true
}, {
  "symbol" : "LYG",
  "companyName" : "Lloyds Banking Group plc",
  "marketCap" : 41814462464,
  "sector" : "Financial Services",
  "industry" : "Banks—Regional",
  "beta" : 1.483138999999999985135445967898704111576080322265625,
  "price" : 2.310000000000000053290705182007513940334320068359375,
  "lastAnnualDividend" : 0.07022699999999999775912584709658403880894184112548828125,
  "volume" : 5825636,
  "exchange" : "New York Stock Exchange",
  "exchangeShortName" : "NYSE",
  "country" : "GB",
  "isEtf" : false,
  "isActivelyTrading" : true
},

代码 ：-

 public void downloadChangePercentage(String api) {

    JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(
            Request.Method.GET,
            api,
            null,
            new Response.Listener<JSONArray>() {
                @RequiresApi(api = Build.VERSION_CODES.N)
                @Override
                public void onResponse(JSONArray response) {
                    // ArrayList<JSONObject> array = new ArrayList<JSONObject>();

                    ArrayList<JSONObject> jsonStockList = new ArrayList<>();

                    for (int i = 0; i < response.length(); i++) {
                        // LOOP over JSON objects and added it to mode/ Stocklist arraylist..

                        try {
                            stockInfo = response.getJSONObject(i);
                            stockDetail = new StockDetails(stockInfo.getString("changesPercentage"), stockInfo.getString("symbol"), stockInfo.getString("price"), stockInfo.getString("name"));
                            stockListArrayList.add(stockDetail);
                            jsonStockList.add(response.getJSONObject(i));
                            searchStockAdapter.notifyDataSetChanged();

                            ArrayList<JSONObject> sortedStockList = sortJSONObject(jsonStockList);
                            for (int j = 0; j < sortedStockList.size(); j++) {
                                logText("sortedData", String.valueOf(sortedStockList.get(j)));
                            }

                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }
                }},
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    Log.i("error", error.toString());
                }
            });
    // Add JsonArrayRequest to the RequestQueue
    requestQueue.add(jsonArrayRequest);

}

ArrayList<JSONObject> sortJSONObject(ArrayList<JSONObject> jsonStockList){
    Collections.sort(jsonStockList, new Comparator<JSONObject>() {
        @Override
        public int compare(JSONObject o1, JSONObject o2) {
            try {
                return Double.compare(o1.getDouble("price"), o2.getDouble("price"));
            } catch (JSONException e) {
                e.printStackTrace();
                return 0;
            }
        }
    });
    return jsonStockList;
}

标签： javaandroidjson

Answer 1

引用您的代码并添加排序逻辑

void callApis(){
    // Initialize a new JsonArrayRequest instance
    JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(
            Request.Method.GET,
            api,
            null,
            new Response.Listener<JSONArray>() {
                @RequiresApi(api = Build.VERSION_CODES.N)
                @Override
                public void onResponse(JSONArray response) {

                    /******** Do exactly like below **********/
                    ArrayList<JSONObject> jsonStockList = new ArrayList<>();
                    
                    for (int i = 0; i<response.length();i++){
                        try {
                            jsonStockList.add(response.getJSONObject(i));
                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }
                    /** pass this stockListArrayList(sorted Data) in view/adapter */
                    
       for (JSONObject stockInfo : sortJSONObject(jsonInfosList)){
            // assigning sorted data in data model 
            StockDetails stockDetail = new StockDetails();
            stockDetail.setCompanyName(stockInfo.getString("companyName"));
            stockDetail.setIndustry(stockInfo.getString("industry"));
            stockDetail.setPrice(stockInfo.getDouble("price"));
            stockDetail.setMarketCap(stockInfo.getLong("marketCap"));
            stockDetail.setSector(stockInfo.getString("sector"));
            stockDetail.setSymbol(stockInfo.getString("symbol"));
            // below (stockListArrayList) is the list which you need to pass in your adapter and notifyDataSetChanged()
            stockListArrayList.add(stockDetail);// stockListArrayList is already decleare in your code
            
        }

                    /*********** end   **********/
                }
            },
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    // Do something when error occurred
                    Log.i("error", error.toString());
                }
            }
    );
    // Add JsonArrayRequest to the RequestQueue
    requestQueue.add(jsonArrayRequest);

}

根据价格对对象进行排序的功能

 ArrayList<JSONObject> sortJSONObject(ArrayList<JSONObject> jsonStockList){
    Collections.sort(jsonStockList, new Comparator<JSONObject>() {
        @Override
        public int compare(JSONObject o1, JSONObject o2) {
            try {
                return Double.compare(o1.getDouble("price"), o2.getDouble("price"));
            } catch (JSONException e) {
                e.printStackTrace();
                return 0;
            }
        }
    });
    return jsonStockList;
}