Question

我正在尝试从GET请求发送一些身份验证标头，我尝试使用Volley JsonObjectRequest调用：

Map<String,String> params=new HashMap<String,String>();
        params.put("token","fghjbvjhnjjk");
        activity.showDialog();
        JsonObjectRequest req = new JsonObjectRequest(Request.Method.GET,url,
                new JSONObject(params), new Response.Listener<JSONObject>() {

            @Override
            public void onResponse(JSONObject response) {
                Log.d(tag, response.toString());
                activity.hideDialog();
                try {
                    activity.onRequestServed(response, code);
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                VolleyLog.d(tag, "Error: " + error.getMessage());
                Log.e(tag, "Site Info Error: " + error.getMessage());
                Toast.makeText(activity.getApplicationContext(),
                        error.getMessage(), Toast.LENGTH_SHORT).show();
                activity.hideDialog();
                try {
                    activity.onRequestServed(null,code);
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        });
        req.setShouldCache(true);

但它显示：

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.hashCode()' on a null object reference
        at com.android.volley.Request.<init>(Request.java:136)
        at com.android.volley.toolbox.JsonRequest.<init>(JsonRequest.java:58)
        at com.android.volley.toolbox.JsonObjectRequest.<init>(JsonObjectRequest.java:47)

我在某处读到你可以通过制作hashmap来传递标题，从而使用该参数创建一个新的JsonObject。也许这适用于POST请求。请帮忙..

Answer 1

嗯，事情很简单，非常精确。将标头传递给GET或POST请求，您需要覆盖JsonObjectRequest类中的getHeaders方法。这是如何做到的：

JsonObjectRequest req = new JsonObjectRequest(Request.Method.GET,url,
                null, new Response.Listener<JSONObject>() {

            @Override
            public void onResponse(JSONObject response) {
                Log.d(tag, response.toString());
                activity.hideDialog();
                try {
                    activity.onRequestServed(response, code);
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                VolleyLog.d(tag, "Error: " + error.getMessage());
                Log.e(tag, "Site Info Error: " + error.getMessage());
                Toast.makeText(activity.getApplicationContext(),
                        error.getMessage(), Toast.LENGTH_SHORT).show();
                activity.hideDialog();
                try {
                    activity.onRequestServed(null,code);
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        }) {

            /**
             * Passing some request headers
             */
            @Override
            public Map<String, String> getHeaders() throws AuthFailureError {
                HashMap<String, String> headers = new HashMap<String, String>();
                //headers.put("Content-Type", "application/json");
                headers.put("key", "Value");
                return headers;
            }
        };

Answer 2

您只需使用下面的var lowerlimit = DateTime.Now.AddMonths(-6); var upperlimit = DateTime.Now.AddMonths(6); var rank =db.rankings.Where(a=>a.Date>lowerlimit && a.Date<upperlimit).ToList();方法

即可

Request.Method.GET

其中参数是

public void methodName(String url,String perameter){
url = url +"?"+ perameters;

JsonObjectRequest req = new JsonObjectRequest(Request.Method.GET,url,
            new JSONObject(params), new Response.Listener<JSONObject>() {
/// your other code
}

Answer 3

我遇到了同样的问题，但我通过仔细检查URL解决了这个问题，确保它是正确的，如：http://192.168.123.102:8080/xxx/xxx

Volley JsonObjectRequest在GET请求中发送标头

3 个答案: