java - 如何获取 Json 响应

Question

我是 android 的新手.. 我想从 restful webservice 得到响应。网络服务工作正常。但是，如何从 android 获得响应。如果我运行该应用程序，请等待进度只来...请任何人帮助

这是我的代码

 public void invokeWS(RequestParams params){
            // Show Progress Dialog
            prgDialog.show();
            // Make RESTful webservice call using AsyncHttpClient object
            AsyncHttpClient client = new AsyncHttpClient();
            client.get("http://192.168.2.2:9999/useraccount/login/dologin", params, new JsonHttpResponseHandler() {
                // When the response returned by REST has Http response code '200'
                @Override
                public void onSuccess(int statusCode, Header[] headers, String response) {
                    // Hide Progress Dialog
                    prgDialog.hide();
                    try {
                        // JSON Object
                        JSONObject obj = new JSONObject(response);
                        // When the JSON response has status boolean value assigned with true
                        if (obj.getBoolean("status")) {
                            Toast.makeText(getActivity().getApplicationContext(), "You are successfully logged in!", Toast.LENGTH_LONG).show();
                            // Navigate to Home screen
                            //navigatetoHomeActivity();
                        }
                        // Else display error message
                        else {
                            errorMsg.setText(obj.getString("error_msg"));
                            Toast.makeText(getActivity().getApplicationContext(), obj.getString("error_msg"), Toast.LENGTH_LONG).show();
                        }
                    } catch (JSONException e) {
                        // TODO Auto-generated catch block
                        Toast.makeText(getActivity().getApplicationContext(), "Error Occured [Server's JSON response might be invalid]!", Toast.LENGTH_LONG).show();
                        e.printStackTrace();

                    }
                }

                // When the response returned by REST has Http response code other than '200'
                @Override
                public void onFailure(int statusCode, Header[] headers, String content, Throwable error) {
                    // Hide Progress Dialog
                    prgDialog.hide();
                    // When Http response code is '404'
                    if (statusCode == 404) {
                        Toast.makeText(getActivity().getApplicationContext(), "Requested resource not found", Toast.LENGTH_LONG).show();
                    }
                    // When Http response code is '500'
                    else if (statusCode == 500) {
                        Toast.makeText(getActivity().getApplicationContext(), "Something went wrong at server end", Toast.LENGTH_LONG).show();
                    }
                    // When Http response code other than 404, 500
                    else {
                        Toast.makeText(getActivity().getApplicationContext(), "Unexpected Error occcured! [Most common Error: Device might not be connected to Internet or remote server is not up and running]", Toast.LENGTH_LONG).show();
                    }

                }
            });
        }

上面代码中，Header[]在onSuccess方法中自动删除。如何修复它。请任何人帮助我!!

Answer 1

首先确保您拥有 list 上的权限:

<uses-permission android:name="android.permission.INTERNET" />

第二个是我建议你使用Volley请求。它易于使用，如果您使用的是 Android Studio，则插件库会更容易。只需将此行添加到您的 app.gradle 依赖项中即可。

compile 'com.mcxiaoke.volley:library:1.0.17'

有关镜像库的更多信息，请单击 here

现在进行示例实现:

public void SendRequest(View view){
        progressDialog.setMessage("Please wait");
        progressDialog.show();

        String url ="YOUR_URL";

        // Request a string response from the provided URL.
        StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
                new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {
                        Log.e("Message", "Response is: " + response);
                        progressDialog.dismiss();

                    }
                }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                Log.e("Message", "Error");
                error.printStackTrace();
                progressDialog.dismiss();
            }
        });

        stringRequest.setTag("YOUR_TAG");
        // Add the request to the RequestQueue.
        queue.add(stringRequest);
    }

并取消您的请求

public void CancelRequest(View view){
        queue.cancelAll("YOUR_TAG");
        Log.e("Message", "Request cancelled");
    }

如果您需要更改要显示的 fragment ，为了更容易处理，只需在暂停或停止时添加它。祝你好运!