在Android中解析对象的JSON数组

Question

我想从此api调用https://api.tfl.gov.uk/Line/25,86,w19/Arrivals?stopPointId=490009219W&app_id=&app_key=获取lineId，destinationName和timeToStation吗？有人可以帮忙提供示例吗？ [ { "$type": "Tfl.Api.Presentation.Entities.Prediction, Tfl.Api.Presentation.Entities", "id": "-480785385", "operationType": 1, "vehicleId": "BJ11DSX", "naptanId": "490009219W", "stationName": "Little Ilford Lane", "lineId": "25", "lineName": "25", "platformName": "B", "direction": "inbound", "bearing": "245", "destinationNaptanId": "", "destinationName": "Oxford Circus", "timestamp": "2016-04-17T16:56:56.463Z", "timeToStation": 1534, "currentLocation": "", "towards": "East Ham or Manor Park", "expectedArrival": "2016-04-17T17:22:31Z", "timeToLive": "2016-04-17T17:23:01Z", "modeName": "bus" }, { "$type": "Tfl.Api.Presentation.Entities.Prediction, Tfl.Api.Presentation.Entities", "id": "1992301652", "operationType": 1, "vehicleId": "BJ11DVA", "naptanId": "490009219W", "stationName": "Little Ilford Lane", "lineId": "25", "lineName": "25", "platformName": "B", "direction": "inbound", "bearing": "245", "destinationNaptanId": "", "destinationName": "Oxford Circus", "timestamp": "2016-04-17T16:56:56.463Z", "timeToStation": 1159, "currentLocation": "", "towards": "East Ham or Manor Park", "expectedArrival": "2016-04-17T17:16:16Z", "timeToLive": "2016-04-17T17:16:46Z", "modeName": "bus" }, { "$type": "Tfl.Api.Presentation.Entities.Prediction, Tfl.Api.Presentation.Entities", "id": "733078946", "operationType": 1, "vehicleId": "BJ11DVG", "naptanId": "490009219W", "stationName": "Little Ilford Lane", "lineId": "25", "lineName": "25", "platformName": "B", "direction": "inbound", "bearing": "245", "destinationNaptanId": "", "destinationName": "Oxford Circus", "timestamp": "2016-04-17T16:56:56.463Z", "timeToStation": 790, "currentLocation": "", "towards": "East Ham or Manor Park", "expectedArrival": "2016-04-17T17:10:07Z", "timeToLive": "2016-04-17T17:10:37Z", "modeName": "bus" } ]

我的AsyncTask被授予

   @Override
    protected JSONObject doInBackground(String... args){
       JSONParser jsonParser = new JSONParser();

        Log.i("URL", url);
        JSONObject json = jsonParser.getJSONFromUrl(url);
        if(json == null) {
            Log.i("Json obj =" , "NULL");
        }
        else{
            return json;
        }
        return new JSONObject();
    }

    @Override
    protected void onPostExecute(JSONObject json){
        progressDialog.dismiss();
        //String shopName ="";
       // String distance="";

        try{
            //Fetching JSON Array
            Log.i("JSON", json.toString());

            jsonData = new JSONArray(json);

            Double arrivalTime= 0.0;

            for(int i=0;i<json.length();i++) {

                try {
                    JSONObject c = json.getJSONObject(i);

                    busNoArray.add(json.getString(TAG_LINEID));
                    destinationArray.add(json.getString(TAG_DESTINATION));

                    arrivalTime = json.getDouble(TAG_TIME) / 60;
                    arrivalTimeArray.add(arrivalTime);

                } catch (JSONException e) {
                    e.printStackTrace();
                }

            }

            adapter = new BusTimeAdapter(BusTimeActivity.this,busNoArray, destinationArray, arrivalTimeArray);
            mListView.setAdapter(adapter);`

有人可以帮我吗？

Answer 1

首先，请确保您已检索JSON字符串，

然后，您可以轻松访问其中的属性，例如

try {
     JSONArray jsonArray = new JSONArray(json);
     JSONObject obj = jsonArray.getJSONObject(0); //0 for just retrieving first object you can loop it
     String myVehicleID = obj.getString("vehicleId"); //To retrieve vehicleId
     //Similarly do it for others as well
    } catch (JSONException e) {
      e.printStackTrace();
    }