Connessione applicativa Android Studio con MySQL

Question

Sto cercando di connettere la mia app Android Studio con il database MySQL ma sto avendo dei problemi durante questo.Ho fatto un semplice login e anche i file PHP che si connettono con DB.

public class AnprSdkMain extends Activity implements OnClickListener{

    private EditText user, pass;
    private Button mSubmit, mRegister;

    // Progress Dialog
    private ProgressDialog pDialog;

    // JSON parser class
    JSONParser jsonParser = new JSONParser();

    //php login script location:

    //localhost :
    //testing on your device
    //put your local ip instead,  on windows, run CMD > ipconfig
    //or in mac's terminal type ifconfig and look for the ip under en0 or en1
    // private static final String LOGIN_URL = "http://xxx.xxx.x.x:1234/webservice/login.php";

    //testing on Emulator:
    private static final String LOGIN_URL = "http://127.0.0.1/anpr/webservice/login.php";

    //testing from a real server:
    //private static final String LOGIN_URL = "http://www.yourdomain.com/webservice/login.php";

    //JSON element ids from repsonse of php script:
    private static final String TAG_SUCCESS = "success";
    private static final String TAG_MESSAGE = "message";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        //setup input fields
        user = (EditText)findViewById(R.id.editText1);
        pass = (EditText)findViewById(R.id.editText2);

        //setup buttons
        mSubmit = (Button)findViewById(R.id.button1);

        //register listeners
        mSubmit.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        switch (v.getId()) {
            case R.id.button1:
                new AttemptLogin().execute();
                break;
            default:
                break;
        }
    }

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

        /**
         * Before starting background thread Show Progress Dialog
         * */
        boolean failure = false;

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(AnprSdkMain.this);
            pDialog.setMessage("Attempting login...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();
        }

        @Override
        protected String doInBackground(String... args) {
            // TODO Auto-generated method stub
            // Check for success tag
            int success;
            String username = user.getText().toString();
            String password = pass.getText().toString();
            try {
                // Building Parameters
                List<NameValuePair> params = new ArrayList<NameValuePair>();
                params.add(new BasicNameValuePair("username", username));
                params.add(new BasicNameValuePair("password", password));

                Log.d("request!", "starting");
                // getting product details by making HTTP request
                JSONObject json = jsonParser.makeHttpRequest(
                        LOGIN_URL, "POST", params);

                // check your log for json response
                Log.d("Login attempt", json.toString());

                // json success tag
                success = json.getInt(TAG_SUCCESS);
                if (success == 1) {
                    Log.d("Login Successful!", json.toString());
                    Intent i = new Intent(AnprSdkMain.this, Lista.class);
                    finish();
                    startActivity(i);
                    return json.getString(TAG_MESSAGE);
                }else{
                    Log.d("Login Failure!", json.getString(TAG_MESSAGE));
                    return json.getString(TAG_MESSAGE);

                }
            } 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 product deleted
            pDialog.dismiss();
            if (file_url != null){
                Toast.makeText(AnprSdkMain.this, file_url, Toast.LENGTH_LONG).show();
            }

        }
    }
}

.

e login.php

//load and connect to MySQL database stuff
require("config.inc.php");

if (!empty($_POST)) {
    //gets user's info based off of a username.
    $query = " 
            SELECT 
                id, 
                username, 
                password
            FROM users 
            WHERE 
                username = :username 
        ";

    $query_params = array(
        ':username' => $_POST['username']
    );

    try {
        $stmt   = $db->prepare($query);
        $result = $stmt->execute($query_params);
    }
    catch (PDOException $ex) {
        // For testing, you could use a die and message. 
        //die("Failed to run query: " . $ex->getMessage());

        //or just use this use this one to product JSON data:
        $response["success"] = 0;
        $response["message"] = "Database Error1. Please Try Again!";
        die(json_encode($response));

    }

    //This will be the variable to determine whether or not the user's information is correct.
    //we initialize it as false.
    $validated_info = false;

    //fetching all the rows from the query
    $row = $stmt->fetch();
    if ($row) {
        //if we encrypted the password, we would unencrypt it here, but in our case we just
        //compare the two passwords
        if ($_POST['password'] === $row['password']) {
            $login_ok = true;
        }
    }

    // If the user logged in successfully, then we send them to the private members-only page 
    // Otherwise, we display a login failed message and show the login form again 
    if ($login_ok) {
        $response["success"] = 1;
        $response["message"] = "Login successful!";
        die(json_encode($response));
    } else {
        $response["success"] = 0;
        $response["message"] = "Invalid Credentials!";
        die(json_encode($response));
    }
} else {
?>
        <h1>Login</h1> 
        <form action="login.php" method="post"> 
            Username:<br /> 
            <input type="text" name="username" placeholder="username" /> 
            <br /><br /> 
            Password:<br /> 
            <input type="password" name="password" placeholder="password" value="" /> 
            <br /><br /> 
            <input type="submit" value="Login" /> 
        </form> 
        <a href="register.php">Register</a>
    <?php
}

e in config.inc.php

<?php 

    // These variables define the connection information for your MySQL database 
    // This is also for the Xampp example,  if you are hosting on your own server,
    //make the necessary changes (mybringback_travis, etc.)
    $username = "root"; 
    $password = ""; 
    $host = "127.0.0.1"; 
    $dbname = "anprscout"; 


    // UTF-8 is a character encoding scheme that allows you to conveniently store 
    // a wide varienty of special characters, like ¢ or €, in your database. 
    // By passing the following $options array to the database connection code we 
    // are telling the MySQL server that we want to communicate with it using UTF-8 
    // See Wikipedia for more information on UTF-8: 
    // http://en.wikipedia.org/wiki/UTF-8 
    $options = array(PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES utf8'); 

    // A try/catch statement is a common method of error handling in object oriented code. 
    // First, PHP executes the code within the try block.  If at any time it encounters an 
    // error while executing that code, it stops immediately and jumps down to the 
    // catch block.  For more detailed information on exceptions and try/catch blocks: 
    // http://us2.php.net/manual/en/language.exceptions.php 
    try 
    { 
        // This statement opens a connection to your database using the PDO library 
        // PDO is designed to provide a flexible interface between PHP and many 
        // different types of database servers.  For more information on PDO: 
        // http://us2.php.net/manual/en/class.pdo.php 
        $db = new PDO("mysql:host={$host};dbname={$dbname};charset=utf8", $username, $password, $options); 
    } 
    catch(PDOException $ex) 
    { 
        // If an error occurs while opening a connection to your database, it will 
        // be trapped here.  The script will output an error and stop executing. 
        // Note: On a production website, you should not output $ex->getMessage(). 
        // It may provide an attacker with helpful information about your code 
        // (like your database username and password). 
        die("Failed to connect to the database: " . $ex->getMessage()); 
    } 

    // This statement configures PDO to throw an exception when it encounters 
    // an error.  This allows us to use try/catch blocks to trap database errors. 
    $db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); 

    // This statement configures PDO to return database rows from your database using an associative 
    // array.  This means the array will have string indexes, where the string value 
    // represents the name of the column in your database. 
    $db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC); 

    // This block of code is used to undo magic quotes.  Magic quotes are a terrible 
    // feature that was removed from PHP as of PHP 5.4.  However, older installations 
    // of PHP may still have magic quotes enabled and this code is necessary to 
    // prevent them from causing problems.  For more information on magic quotes: 
    // http://php.net/manual/en/security.magicquotes.php 
    if(function_exists('get_magic_quotes_gpc') && get_magic_quotes_gpc()) 
    { 
        function undo_magic_quotes_gpc(&$array) 
        { 
            foreach($array as &$value) 
            { 
                if(is_array($value)) 
                { 
                    undo_magic_quotes_gpc($value); 
                } 
                else 
                { 
                    $value = stripslashes($value); 
                } 
            } 
        } 

        undo_magic_quotes_gpc($_POST); 
        undo_magic_quotes_gpc($_GET); 
        undo_magic_quotes_gpc($_COOKIE); 
    } 
    header('Content-Type: text/html; charset=utf-8'); 
    session_start(); 

.

Il problema visualizzato quando si esegue le applicazioni sono:

07-28 18:15:34.815      340-347/com.birdorg.anpr.sdk.simple.camera.example E/Buffer Error﹕ Error converting result java.lang.NullPointerException
07-28 18:15:34.815      340-347/com.birdorg.anpr.sdk.simple.camera.example E/JSON Parser﹕ Error parsing data org.json.JSONException: End of input at character 0 of
07-28 18:15:34.825      340-347/com.birdorg.anpr.sdk.simple.camera.example W/dalvikvm﹕ threadid=7: thread exiting with uncaught exception (group=0x4001d800)
07-28 18:15:34.855      340-347/com.birdorg.anpr.sdk.simple.camera.example E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1
    java.lang.RuntimeException: An error occured while executing doInBackground()
            at android.os.AsyncTask$3.done(AsyncTask.java:200)
            at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
            at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
            at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
            at java.util.concurrent.FutureTask.run(FutureTask.java:137)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561)
            at java.lang.Thread.run(Thread.java:1096)
     Caused by: java.lang.NullPointerException
            at com.birdorg.anpr.sdk.simple.camera.example.AnprSdkMain$AttemptLogin.doInBackground(AnprSdkMain.java:116)
            at com.birdorg.anpr.sdk.simple.camera.example.AnprSdkMain$AttemptLogin.doInBackground(AnprSdkMain.java:80)
            at android.os.AsyncTask$2.call(AsyncTask.java:185)
            at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
            at java.util.concurrent.FutureTask.run(FutureTask.java:137)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561)
            at java.lang.Thread.run(Thread.java:1096)
07-28 18:15:35.025      340-340/com.birdorg.anpr.sdk.simple.camera.example W/IInputConnectionWrapper﹕ showStatusIcon on inactive InputConnection
07-28 18:15:35.724      340-340/com.birdorg.anpr.sdk.simple.camera.example E/WindowManager﹕ Activity com.birdorg.anpr.sdk.simple.camera.example.AnprSdkMain has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@4a22d5a0 that was originally added here
    android.view.WindowLeaked: Activity com.birdorg.anpr.sdk.simple.camera.example.AnprSdkMain has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@4a22d5a0 that was originally added here
            at android.view.ViewRoot.<init>(ViewRoot.java:247)
            at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:148)
            at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
            at android.view.Window$LocalWindowManager.addView(Window.java:424)
            at android.app.Dialog.show(Dialog.java:241)
            at com.birdorg.anpr.sdk.simple.camera.example.AnprSdkMain$AttemptLogin.onPreExecute(AnprSdkMain.java:94)
            at android.os.AsyncTask.execute(AsyncTask.java:391)
            at com.birdorg.anpr.sdk.simple.camera.example.AnprSdkMain.onClick(AnprSdkMain.java:73)
            at android.view.View.performClick(View.java:2408)
            at android.view.View$PerformClick.run(View.java:8816)
            at android.os.Handler.handleCallback(Handler.java:587)
            at android.os.Handler.dispatchMessage(Handler.java:92)
            at android.os.Looper.loop(Looper.java:123)
            at android.app.ActivityThread.main(ActivityThread.java:4627)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:521)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
            at dalvik.system.NativeStart.main(Native Method)

.

Sono nuovo a Android Studio.Ho davvero bisogno di aiuto con questo

Answer 1

Se si sta tentando di connettersi tramite l'emulatore, utilizzare l'indirizzo IP 10.0.2.2 invece di 127.0.0.1.Questo link parla di più.

Answer 2

Building App che comunica con il server Web in modo da costruire due app (o forse di più) che comunica è una delle cose più difficili nella programmazione del computer perché è difficile sapere da che parte è buggy (e talvolta, entrambi sono ...). .

Ti suggerisco un punto di partenza I Uso con Great Succes: Inizia con programmazione, da solo, il lato PHP.Basta chiamarlo durante l'utilizzo dell'URL su cui metti il parametro.Quando sarà "echo", come stai chiamando il PHP tramite il tuo web Brower, vedrai il risultato. Quando va bene, aggiungi un sistema "log" in te Php.In questo modo:

function debug_log($string_db)
{
    // Prepare string with date and time
    $the_date = date("[ d/m/Y - H:i:s ] ");
    $to_save = $the_date.$string_db."\r";   // and add the string to log

    // Open file: write at he the end
    $handle = fopen("call.log","a");

    // Save string
    fwrite($handle,$to_save,strlen($to_save));

    fclose($handle);    // bye bye
}

.

Usalo come (ad es.): debug_log ("interno primo loop");

È molto "di base", ma questo salverà su disco e non "echo", questo non disturberà l'app Android ma ti permetterà di dare un'occhiata a ciò che stai facendo PHP.

Una volta che lo hai fatto, torna al Dev Android come, come questa volta, sarai sicuro che, in caso di problemi, è sul lato Android.