android - 如何通过在android中重复循环来创建json对象？

Question

我想通过在 while 循环中获取形状文件的点来创建 Json 对象。形状文件包含 73 个点。我将形状文件的点存储在 json oject 中，并在循环中将对象添加到 ArrayList，在 while 下方循环我从 ArrayList 中一个一个地检索对象并将其存储在 JsonArray 中，但这里的问题是 shapefile 的最后一个记录点在 arraylist 中存储了 73 次。如何解决这个问题请帮助我。

这是我的代码

try {

        File file= new File(Environment.getDataDirectory().getAbsolutePath()+"/ne_50m_admin_0_tiny_countries.shp");
        Long fileLength=file.length();
        Log.d("FileLength is","file"+fileLength);
        String shpFile = Environment.getDataDirectory().getAbsolutePath().toString()+"/ne_50m_admin_0_tiny_countries.shp";
        //String shpFile = Environment.getDataDirectory().getAbsolutePath().toString()+"/ne_50m_admin_0_breakaway_disputed_areas.shp";
        ShapeReader reader = new ShapeReader(shpFile, true);
        ShapeType shpType=reader.getHeader().getShapeType();
        JSONObject jObject = new JSONObject();
        JSONObject wkidJson = new JSONObject();
        jObject.put("objectIdFieldName","OBJECTID");
        jObject.put("globalIdFieldName","");
        jObject.put("geometryType",shpType);
        wkidJson.put("wkid", new Integer(102100));
        jObject.put("spatialReference",wkidJson);
        JSONArray fieldsList = new JSONArray();
        JSONObject idJson = new JSONObject();
        JSONObject yJson = new JSONObject();
        JSONObject xJson = new JSONObject();
        idJson.put( "name","OBJECTID");
        idJson.put("alias", "OBJECTID");
        idJson.put("type", "esriFieldTypeOID");
        yJson.put( "name","y");
        yJson.put("alias", "y");
        yJson.put("type", "esriFieldTypeDouble");
        xJson.put( "name","x");
        xJson.put("alias", "x");
        xJson.put("type", "esriFieldTypeDouble");
        fieldsList.put(idJson);
        fieldsList.put(yJson);
        fieldsList.put(xJson);
        jObject.put("fields",fieldsList);
        JSONObject geomJson = new JSONObject();
        JSONObject attJson = new JSONObject();
        JSONObject featuresJson = new JSONObject();
        JSONArray featuresList = new JSONArray();
        Log.d("Header info is","Header"+reader.getHeader().getFileLength());
        recordshape=reader.new Record();
        ArrayList a= new ArrayList();
        while (reader.hasNext())
        {

            if(recordshape.end < fileLength)
            {
                if(shpType==ShapeType.POINT)
                {
                    recordshape=reader.nextRecord();
                    int recordNumber=recordshape.number;
                    double Xcoordinate= recordshape.minX;
                    double Ycoordinate=recordshape.minY;
                    Log.d("Xcoordinate info is","Xcoordinate"+Xcoordinate);
                    Log.d("Ycoordinate info is","Ycoordinate"+Ycoordinate);
                    geomJson.put("x", Xcoordinate);
                    geomJson.put("y", Ycoordinate);
                    attJson.put("OBJECTID", recordNumber);
                    attJson.put("y", Ycoordinate);
                    attJson.put("x", Xcoordinate);
                }

            }
            else
                break;

            featuresJson.put("geometry", geomJson);
            featuresJson.put("attributes", attJson);
            a.add(featuresJson);
            Log.d("featuresJson info is","featuresJson"+featuresJson);
         }
        Log.d("featuresJson info is","featuresJson"+featuresJson);
        Log.d("size info is","size"+a.size());
        for(int i=0;i<a.size();i++)
        {
        featuresList.put(a.get(i));
        }

        Log.d("featuresList info is","featuresList"+featuresList);
        jObject.put("features",featuresList);
        String jsonString = jObject.toString();

        jsonString = jsonString.replace("\\" , "");

        FileWriter writeFile = new FileWriter(Environment.getDataDirectory().getAbsolutePath().toString()+"/Test.json");
        BufferedWriter out = new BufferedWriter(writeFile);
        out.write(jsonString);
        out.flush();
        out.close();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        Log.d("Error","Message"+e.getMessage());
    }catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
            Log.d("Exception","Message"+e.getMessage());
    }

我要的json格式是

{
"objectIdFieldName": "OBJECTID",
"globalIdFieldName": "",
"geometryType": "esriGeometryPoint",
"spatialReference": {
    "wkid": 102100
},
"fields": [
    {
        "name": "OBJECTID",
        "alias": "OBJECTID",
        "type": "esriFieldTypeOID"
    },
    {
        "name": "y",
        "alias": "y",
        "type": "esriFieldTypeDouble"
    },
    {
        "name": "x",
        "alias": "x",
        "type": "esriFieldTypeDouble"
    }
],
"features": [
    {
        "geometry": {
            "x": -13021472.272599999,
            "y": 4046325.7190999985
        },
        "attributes": {
            "OBJECTID": 212,
            "y": 4046325.7191,
            "x": -13021472.2726
        }
    },
    {
        "geometry": {
            "x": -13021124.9134,
            "y": 4046747.3976000026
        },
        "attributes": {
            "OBJECTID": 232,
            "y": 4046747.3976,
            "x": -13021124.9134

        }
    }
]

请帮帮我谢谢。

Answer 1

在您的循环中，您一遍又一遍地将值放入同一个 json 对象中。因此，当您对它进行 jsonify 处理时，您的数组包含 n* 个相同的对象。

您需要创建新对象以添加到循环的每次传递中。

这三个声明必须在循环内移动:

JSONObject geomJson = new JSONObject();
JSONObject attJson = new JSONObject();
JSONObject featuresJson = new JSONObject();