java - 安卓 : how to return JSONObject from Volley OnRequest StringRequest method

Question

我需要通过将字符串数据的值分配给 OnResponse() scpoe 之外的另一个方法来传递响应字符串，以便我可以通过调用该方法从中返回 JSONObject，但它总是返回 null

我需要的只是从 Volley stringrequest 获取 JSONObject，因为响应是 xml "

<?xml version="1.0" encoding="utf-8"?>
<string xmlns="http://tempuri.org/">........</string>

这是我的代码

static String data;

private  void driverByIdStringRequest(int ID,final Context context){
        RequestQueue queue = VolleySingleton.getInstance(context.getApplicationContext()).getRequestQueue();
        // Request a string response from the provided URL.
        StringRequest stringRequest = new StringRequest(Request.Method.GET, url+ID,
                new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {
                        response = response.replaceAll("<?xml version=\"1.0\" encoding=\"utf-8\"?>", "");
                        response = response.replaceAll("<string xmlns=\"http://tempuri.org/\">", "");
                        response = response.replaceAll("</string>", "");
                        String data = response.substring(40);
                    }
                }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                Log.d("Error : ", error.toString());
            }
        });
        VolleySingleton.getInstance(context).addToRequestQueue(stringRequest);
    }


public JSONObject GetDriverById(int ID,Context context){
    driverByIdStringRequest(ID, context);
    JSONObject json = JSONObject(data);
    return json;
}

Answer 1

如果来自 StringRequest 的字符串响应始终具有以下格式:

<?xml version="1.0" encoding="utf-8"?>
<string xmlns="http://tempuri.org/">........</string>

其中........是你想要获取的JSONObject，我建议你像下面这样处理String响应:

...
String jsonString = stringResponse;

jsonString = jsonString.replace("<?xml version=\"1.0\" encoding=\"utf-8\"?>"," ");
jsonString = jsonString.replace("<string xmlns=\"tempuri.org/\">"," ");
jsonString = jsonString.replace("</string>"," ");
try {
    JSONObject jsonObject = new JSONObject(jsonString);
} catch (JSONException e) {
    e.printStackTrace();
}
...

回到你的代码，data当然是NULL，因为JSONObject json = JSONObject(data);在调用的Request中的onResponse之前调用。对于您的问题，建议您引用我在以下问题中的回答:

Android: How to return async JSONObject from method using Volley?

希望这有帮助!