Question

I’ve written some code to parse the Google Distance Matrix JSON response received by my Android program. The only piece of data I’m interested in is in the “distance” “value” node.

My code works, but it seems like there must be an easier way to do this. The distance value node is nested pretty deep inside the JSON, but is it really necessary to go through every layer of the JSON to get to the field you want?

Here’s my JSON response:

{
"destination_addresses" : [
  "5660 Baltimore National Pike, Ingleside Shopping Center, Catonsville, MD 21228, USA"
],
"origin_addresses" : [ "Hilltop Cir, Baltimore, MD 21250, USA" ],
"rows" : [
  {
     "elements" : [
        {
           "distance" : {
              "text" : "3.1 mi",
              "value" : 4922 <--THE FIELD I WANT TO EXTRACT
           },
           "duration" : {
              "text" : "11 mins",
              "value" : 666
           },
           "status" : "OK"
        }
     ]
  }
],
"status" : "OK"
}

And here is the code I used to pull out the distance value:

    private double extractDistance(JSONObject json) {
    JSONArray rowsArray = null;
    double distanceInMiles = -1;
    try {
        // Getting Array of Distance Matrix Results
        rowsArray = json.getJSONArray("rows");
        JSONObject rowsObject = rowsArray.getJSONObject(0);//only one element in this array
        JSONArray elementsArray = rowsObject.getJSONArray("elements");
        JSONObject elementsObject = elementsArray.getJSONObject(0);//only one element in this array
        JSONObject distanceObject = elementsObject.getJSONObject("distance");
        distanceInMiles = (distanceObject.getDouble("value"))/1609.344; //distance in meters converted to miles
    }
    catch (JSONException e) {
        e.printStackTrace();
    }
    return distanceInMiles;
}

Thanks!

Answer 1

Unless you want to go into writing a custom regular expression to search the json string, yes that’s going to be the best way of accessing it (and the easiest). Is there a reason you feel you need to access it ‘more efficiently’?