JSONObject getInt(string) 方法导致 java.lang.RuntimeException。 Android工作室

Question

我正在尝试检查用户是否输入了正确的用户 ID 和密码以登录应用程序。我的数据库已经在线部署。一切运行顺利，直到我得到结果以检查是否允许用户继续。但问题是我没有得到任何结果。相反，我在 JSONObject 的 getInt(String) 方法上得到了一个 java.lang.RuntimeException。这是我的 LoginActivity.java

public class LoginActivity extends AppCompatActivity {

    JSONParser jsonParser = new JSONParser();
    // single product url
    private static final String url_user_check_login = "####/android_connect/check_user_login.php?username=#### & password=#####";
     int success=0;
    String id="";
    String password="";
    private static final String TAG_SUCCESS = "success";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

//        Defining onClickListener for Login Button
        Button loginBtn=(Button) findViewById(R.id.login_btn);
        loginBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
//                Check credentials
                EditText phone=(EditText)findViewById(R.id.phone_txt);
                EditText pwd=(EditText)findViewById(R.id.password_txt);
                id=phone.getText().toString();
                password=pwd.getText().toString();
                new CheckUserLogin().execute();

            }
        });
    }

    class CheckUserLogin extends AsyncTask<String, String, String> {

        protected String doInBackground(String... params) {


                    // Check for success tag

                    try {
                        // Building Parameters
                        List<NameValuePair> params1 = new ArrayList<NameValuePair>();
                        params1.add(new BasicNameValuePair("id", id));
                        params1.add(new BasicNameValuePair("password", password));

                        JSONObject json = jsonParser.makeHttpRequest(
                                url_user_check_login, "GET", params1);


                        // json success tag
                        success = json.getInt(TAG_SUCCESS);//This is the line where i am getting the exception

                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
//                }
//            });

            return null;
        }

        /**
         * After completing background task Dismiss the progress dialog
         * **/
        protected void onPostExecute(String file_url) {
            // dismiss the dialog once got all details
            if (success == 1) {

                Intent intent=new Intent(getApplicationContext(), RideDetailsActivity.class);
                startActivity(intent);

            }
        }
    }
}

这是我正在使用的 php 个文件。

db_connect.php

db_connect.php
<?php

/**
 * A class file to connect to database
 */
class DB_CONNECT {

    // constructor
    function __construct() {
        // connecting to database
        $this->connect();
    }

    // destructor
    function __destruct() {
        // closing db connection
        $this->close();
    }

    /**
     * Function to connect with database
     */
    function connect() {
        // import database connection variables
        require_once __DIR__ . '/db_config.php';

        // Connecting to mysql database
        $con = mysql_connect(DB_SERVER, DB_USER, DB_PASSWORD) or die(mysql_error());

        // Selecing database
        $db = mysql_select_db(DB_DATABASE) or die(mysql_error()) or die(mysql_error());

        // returing connection cursor
        return $con;
    }

    /**
     * Function to close db connection
     */
    function close() {
        // closing db connection
        mysql_close();
    }

}

?>

db_config.php

db_config.php
<?php

/*
 * All database connection variables
 */

define('DB_USER', "####"); // db user
define('DB_PASSWORD', "####"); // db password (mention your db password here)
define('DB_DATABASE', "####"); // database name
define('DB_SERVER', "###.###.###); // db server
?>

check_user_login.php

check_user_login.php
<?php

/*
 * Following code will check user credentials for log in
 * uid and password are used to check if the user has permission to log in
 */

// array for JSON response
$response = array();

// include db connect class
require_once __DIR__ . '/db_connect.php';

// connecting to db
$db = new DB_CONNECT();

// check for post data
if (isset($_GET["id"]) && isset($_GET["password"])) {
    $id = $_GET['id'];
    $password = $_GET['password'];

    // get a product from products table
    $result = mysql_query("SELECT * FROM tb_login WHERE id = $id AND password = $password");

    if (!empty($result)) {
        // check for empty result
        if (mysql_num_rows($result) > 0) {

            // success
            $response["success"] = 1;
            $response["message"] = "User found";

            // echoing JSON response
            echo json_encode($response);
        } else {
            // no user found
            $response["success"] = 0;
            $response["message"] = "No user found";

            // echo no users JSON
            echo json_encode($response);
        }
    } else {
        // no user found
        $response["success"] = 0;
        $response["message"] = "No user found";

        // echo no users JSON
        echo json_encode($response);
    }
} else {
    // required field is missing
    $response["success"] = 0;
    $response["message"] = "Required field(s) is missing";

    // echoing JSON response
    echo json_encode($response);
}
?>

这是异常的堆栈跟踪

FATAL EXCEPTION: AsyncTask #4
                                                                   java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask.done(AsyncTask.java:299)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352)
at java.util.concurrent.FutureTask.setException(FutureTask.java:219)
at java.util.concurrent.FutureTask.run(FutureTask.java:239)
at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:230)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
at java.lang.Thread.run(Thread.java:838)
Caused by: java.lang.NullPointerException
at com.heycabs.heycabs.LoginActivity$CheckUserLogin.doInBackground(LoginActivity.java:100)
at com.heycabs.heycabs.LoginActivity$CheckUserLogin.doInBackground(LoginActivity.java:59)
at android.os.AsyncTask.call(AsyncTask.java:287)
at java.util.concurrent.FutureTask.run(FutureTask.java:234)
at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:230) 
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080) 
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573) 
at java.lang.Thread.run(Thread.java:838)

我也不知道，所以我想问我是否必须提及数据库的端口号以及数据库服务器的 IP 地址？我完全不熟悉 php 并在 android 中使用 JSON。因此，在指出任何明显的错误时，请慎重考虑。谢谢。

Answer 1

查看此页面。 http://danielnugent.blogspot.com/2015/06/updated-jsonparser-with.html 根据您在评论中发布的教程，您使用的 JSONParser 似乎是问题所在。

这里是更新 JSONParser 的代码，如果您只想尝试将其插入您的代码并查看它是否能解决您的问题。如果您想了解更多信息，请单击 link。

   import android.util.Log;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.util.HashMap;

public class JSONParser {

    String charset = "UTF-8";
    HttpURLConnection conn;
    DataOutputStream wr;
    StringBuilder result;
    URL urlObj;
    JSONObject jObj = null;
    StringBuilder sbParams;
    String paramsString;

    public JSONObject makeHttpRequest(String url, String method,
                                      HashMap<String, String> params) {

        sbParams = new StringBuilder();
        int i = 0;
        for (String key : params.keySet()) {
            try {
                if (i != 0){
                    sbParams.append("&");
                }
                sbParams.append(key).append("=")
                        .append(URLEncoder.encode(params.get(key), charset));

            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            }
            i++;
        }

        if (method.equals("POST")) {
            // request method is POST
            try {
                urlObj = new URL(url);

                conn = (HttpURLConnection) urlObj.openConnection();

                conn.setDoOutput(true);

                conn.setRequestMethod("POST");

                conn.setRequestProperty("Accept-Charset", charset);

                conn.setReadTimeout(10000);
                conn.setConnectTimeout(15000);

                conn.connect();

                paramsString = sbParams.toString();

                wr = new DataOutputStream(conn.getOutputStream());
                wr.writeBytes(paramsString);
                wr.flush();
                wr.close();

            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        else if(method.equals("GET")){
            // request method is GET

            if (sbParams.length() != 0) {
                url += "?" + sbParams.toString();
            }

            try {
                urlObj = new URL(url);

                conn = (HttpURLConnection) urlObj.openConnection();

                conn.setDoOutput(false);

                conn.setRequestMethod("GET");

                conn.setRequestProperty("Accept-Charset", charset);

                conn.setConnectTimeout(15000);

                conn.connect();

            } catch (IOException e) {
                e.printStackTrace();
            }

        }

        try {
            //Receive the response from the server
            InputStream in = new BufferedInputStream(conn.getInputStream());
            BufferedReader reader = new BufferedReader(new InputStreamReader(in));
            result = new StringBuilder();
            String line;
            while ((line = reader.readLine()) != null) {
                result.append(line);
            }

            Log.d("JSON Parser", "result: " + result.toString());

        } catch (IOException e) {
            e.printStackTrace();
        }

        conn.disconnect();

        // try parse the string to a JSON object
        try {
            jObj = new JSONObject(result.toString());
        } catch (JSONException e) {
            Log.e("JSON Parser", "Error parsing data " + e.toString());
        }

        // return JSON Object
        return jObj;
    }
}

JSONObject getInt(string) 方法导致 java.lang.RuntimeException。 Android工作室

JSONObject getInt(string) method causing java.lang.RuntimeException. Android Studio

php

java

android

json

database-server