Here you get JSONObject so change this line:
JSONArray jsonArray = new JSONArray(readlocationFeed);
with following:
JSONObject jsnobject = new JSONObject(readlocationFeed);
and after
JSONArray jsonArray = jsnobject.getJSONArray("locations");
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject explrObject = jsonArray.getJSONObject(i);
}