排球库中JsonObjectRequest出错

I am trying to implement a JsonRequestObject with Volley library on android

我想在android上用Volley库实现一个JsonRequestObject

this is the code of the method

这是方法的代码

private void makeJsonObjReq() {
    showProgressDialog();
    JsonObjectRequest jsonObjReq = new JsonObjectRequest(Method.GET,
            Const.URL_JSON_OBJECT, null,
            new Response.Listener<JSONObject>() {

                @Override
                public void onResponse(JSONObject response) {
                    Log.d(TAG, response.toString());
                    msgResponse.setText(response.toString());
                    hideProgressDialog();
                }
            }, new Response.ErrorListener() {

                @Override
                public void onErrorResponse(VolleyError error) {
                    VolleyLog.d(TAG, "Error: " + error.getMessage());
                    hideProgressDialog();
                }
            }) {

and this is the error message

这是错误信息

Error:(71, 34) error: reference to JsonObjectRequest is ambiguous both constructor JsonObjectRequest(int,String,String,Listener,ErrorListener) in JsonObjectRequest and constructor JsonObjectRequest(int,String,JSONObject,Listener,ErrorListener) in JsonObjectRequest match

错误：（71,34）错误：对JsonObjectRequest的引用与JsonObjectRequest中的构造函数JsonObjectRequest（int，String，String，Listener，ErrorListener）和JsonObjectRequest匹配中的构造函数JsonObjectRequest（int，String，JSONObject，Listener，ErrorListener）不一致

1 个解决方案

#1

Try passing blank string in constructor instead of null.

尝试在构造函数中传递空字符串而不是null。

private void makeJsonObjReq() {
showProgressDialog();
JsonObjectRequest jsonObjReq = new JsonObjectRequest(Method.GET,
        Const.URL_JSON_OBJECT, "",
        new Response.Listener<JSONObject>() {

            @Override
            public void onResponse(JSONObject response) {
                Log.d(TAG, response.toString());
                msgResponse.setText(response.toString());
                hideProgressDialog();
            }
        }, new Response.ErrorListener() {

            @Override
            public void onErrorResponse(VolleyError error) {
                VolleyLog.d(TAG, "Error: " + error.getMessage());
                hideProgressDialog();
            }
        }) {

The reason it was not working is because when you pass parameters in constructor, it tries to match them with available constructors on three basic criterias:

它不起作用的原因是因为当你在构造函数中传递参数时，它会尝试将它们与三个基本标准上的可用构造函数进行匹配：

The total number of parameters you have passed.
您传递的参数总数。
The ordering of those parameters like (int, String, int);
这些参数的排序如（int，String，int）;
And the type of parameter passed.
并且传递了参数的类型。

In your case, based on above conditions it matched to two constructors. The value of String or JSONObject can be null thats why it was showing you ambiguous error on JsonObjectRequest(int,String,String,Listener,ErrorListener) and JsonObjectRequest(int,String,JSONObject,Listener,ErrorListener). We just passed blank String as argument so that it now knows that the third argument is of type string.

在您的情况下，基于上述条件，它与两个构造函数匹配。 String或JSONObject的值可以为null，这就是为什么它在JsonObjectRequest（int，String，String，Listener，ErrorListener）和JsonObjectRequest（int，String，JSONObject，Listener，ErrorListener）上显示模糊错误的原因。我们只传递空字符串作为参数，以便它现在知道第三个参数是字符串类型。

#1