我在http://202.158.68.155:7890/cobra/api/getDataByNopol中有API

如果我在邮递员中测试其工作，但在android凌空错误中为空

final RequestQueue requestQueue= Volley.newRequestQueue(getactivity());
    StringRequest stringRequest = new StringRequest(Request.Method.POST,"http://202.158.68.155:7890/cobra/api/getDataByNopol",new Response.Listener<String>() {
        @Override
        public void onResponse(String response) {
            hideDialog();
            Log.e(TAG,"Response Detail -> "+response);
            requestQueue.stop();
        }
    },new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            VolleyLog.d("ERROR",error.getMessage());
            Toast.makeText(getactivity(),"ERROR "+error.getMessage(),Toast.LENGTH_LONG).show();
            requestQueue.stop();
        }
    }) {
        @Override
        protected Map<String,String> getParams() throws AuthFailureError {
            Map<String,String> param = new HashMap<String,String>();

            param.put("nopol","L 6967 TJ");
            param.put("username","uat2");
            param.put("token","02E184D3C82B6DA4750A214C4");
            return param;
        }
    };
    requestQueue.add(stringRequest);
    AppController.getInstance().addToRequestQueue(stringRequest,tag_json);
}

如何处理这种情况？