Question

我试图通过android studio中的volley将json对象发送到服务器（eclipse + tomcat中的mvc spring项目正在侦听）但应用程序崩溃了。我是凌空图书馆的新手。此外，json对象由在组合框和textview中的用户输入获得的数据组成。

登录活动：

Logcat错误：

package com.example.mujtaba.quizzer;

import android.app.ProgressDialog;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.Spinner;
import android.widget.TextView;

import com.android.volley.Cache;
import com.android.volley.Network;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.VolleyLog;
import com.android.volley.toolbox.BasicNetwork;
import com.android.volley.toolbox.DiskBasedCache;
import com.android.volley.toolbox.HurlStack;
import com.android.volley.toolbox.StringRequest;
import com.example.mujtaba.quizzer.Activity.QuizMaking;
import com.example.mujtaba.quizzer.Activity.QuizTaking;

import org.w3c.dom.Text;

import java.util.HashMap;
import java.util.Map;

public class Login extends AppCompatActivity {
    private Button button;
    private TextView username;
    private TextView password;
    private Spinner role;
    private String url = "http://localhost:8080/users/signup";
    private RequestQueue queue;
    private ProgressDialog progress;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);

        username=(TextView) findViewById(R.id.username);
        password=(TextView) findViewById(R.id.password);
        button=(Button) findViewById(R.id.button);
        role = (Spinner) findViewById(R.id.role);

// Create an ArrayAdapter using the string array and a default spinner layout
        ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,
                R.array.role_spinner, android.R.layout.simple_spinner_item);
// Specify the layout to use when the list of choices appears
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
// Apply the adapter to the spinner
        role.setAdapter(adapter);
    }

    public void Quiz(View v) {   //select a new activity on the basis of role

// Instantiate the cache
        Cache cache = new DiskBasedCache(getCacheDir(), 1024 * 1024); // 1MB cap

// Set up the network to use HttpURLConnection as the HTTP client.
        Network network = new BasicNetwork(new HurlStack());

// Instantiate the RequestQueue with the cache and network.
        queue = new RequestQueue(cache, network);

// Start the queue
        queue.start();


        StringRequest MyStringRequest = new StringRequest(Request.Method.POST, url, new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                //This code is executed if the server responds, whether or not the response contains data.
                //The String 'response' contains the server's response.
            }
        }, new Response.ErrorListener() { //Create an error listener to handle errors appropriately.
            @Override
            public void onErrorResponse(VolleyError error) {
                //This code is executed if there is an error.
            }
        }) {
            protected Map<String, String> getParams() {
                Map<String, String> MyData = new HashMap<String,String>();
                MyData.put("Username", username.getText().toString() ); //Add the data you'd like to send to the server.
                MyData.put("Password",password.getText().toString());
                MyData.put("Role",role.getSelectedItem().toString());
                MyData.put("Score","0");
                return MyData;
            }
        };

        queue.add(MyStringRequest);
    }
}

Android在发送json对象时崩溃

0 个答案: