I'm working on an app and I am having some trouble getting the login and registration to work. Here is the code I have for my registration.

Code:
public class RegisterActivity extends Activity {
    Button btnRegister;
    Button btnLinkToLogin;
    EditText inputFullName;
    EditText inputEmail;
    EditText inputPassword;
    TextView registerErrorMsg;
 
    //JSON Response node names
    private static String KEY_SUCCESS = "success";
    private static String KEY_UID = "uid";
    private static String KEY_NAME = "name";
    private static String KEY_EMAIL = "email";
    private static String KEY_CREATED_AT = "created_at";
 
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_register);
 
        // Importing all assets like buttons, text fields
        inputFullName = (EditText) findViewById(R.id.registerName);
        inputEmail = (EditText) findViewById(R.id.registerEmail);
        inputPassword = (EditText) findViewById(R.id.registerPassword);
        btnRegister = (Button) findViewById(R.id.btnRegister);
        btnLinkToLogin = (Button) findViewById(R.id.btnLinkToLoginScreen);
        registerErrorMsg = (TextView) findViewById(R.id.register_error);
 
        // Register Button Click event
        btnRegister.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                //String name = inputFullName.getText().toString();
                //String email = inputEmail.getText().toString();
                //String password = inputPassword.getText().toString();
                
                new RegisterTask().execute();
            }
        });
 
        // Link to Login Screen
        btnLinkToLogin.setOnClickListener(new View.OnClickListener() {
 
            public void onClick(View view) {
                Intent i = new Intent(getApplicationContext(),
                        LoginActivity.class);
                startActivity(i);
                // Close Registration View
                finish();
            }
        });
    }

class RegisterTask extends AsyncTask<String, String, String> {
	int success = 0;
	
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
    }

    @Override
    protected String doInBackground(String... args) {
        String email = inputEmail.getText().toString();
        String password = inputPassword.getText().toString();
        String name = inputFullName.getText().toString();

        UserFunctions userFunction = new UserFunctions();
        JSONObject json = userFunction.registerUser(name, email, password);

        Log.d("Create Response", json.toString());

        try {
            success = json.getInt(KEY_SUCCESS);
            if (success == 1) {
                // DATABASE HANDLER
                // user successfully logged in
                // Store user details in SQLite Database
                DatabaseHandler db = new DatabaseHandler(
                        getApplicationContext());
                JSONObject json_user = json.getJSONObject("user");

                // Clear all previous data in database
                userFunction.logoutUser(getApplicationContext());

                db.addUser(json_user.getString(KEY_NAME),
                        json_user.getString(KEY_EMAIL),
                        json_user.getString(KEY_UID),
                        json_user.getString(KEY_CREATED_AT));

			}
		} catch (JSONException e) {
            e.printStackTrace();
        }
        return null;
    }

    protected void onPostExecute(String file_url) {
	if (success == 1) {
			Intent dashboard = new Intent(getApplicationContext(), LoginActivity.class);
			dashboard.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
			startActivity(dashboard);
			finish();
 	}else{
       	//tvLError.setText("Incorrect username/password");

     }
    }
}
}
And I am having trouble with my php script as well, I'm not sure what is wrong with that.

Code:
<?php
 
class DB_Functions {
 
    private $db;
 
    //put your code here
    // constructor
    function __construct() {
        require_once 'DB_Connect.php';
        // connecting to database
        $this->db = new DB_Connect();
        $this->db->connect();
    }
 
    // destructor
    function __destruct() {
 
    }
 
    /**
     * Storing new user
     * returns user details
     */
    public function storeUser($name, $email, $password) {
        $uuid = uniqid('', true);
        $hash = $this->hashSSHA($password);
        $encrypted_password = $hash["encrypted"]; // encrypted password
        $salt = $hash["salt"]; // salt
        $result = mysql_query("INSERT INTO users(unique_id, name, email, encrypted_password, salt, created_at) VALUES('$uuid', '$name', '$email', '$encrypted_password', '$salt', NOW())");
        // check for successful store
        if ($result) {
            // get user details
            $uid = mysql_insert_id(); // last inserted id
            $result = mysql_query("SELECT * FROM users WHERE uid = $uid");
            // return user details
            return mysql_fetch_array($result);
        } else {
            return false;
        }
    }
 
    /**
     * Get user by email and password
     */
    public function getUserByEmailAndPassword($email, $password) {
        $result = mysql_query("SELECT * FROM users WHERE email = '$email'") or die(mysql_error());
        // check for result
        $no_of_rows = mysql_num_rows($result);
        if ($no_of_rows > 0) {
            $result = mysql_fetch_array($result);
            $salt = $result['salt'];
            $encrypted_password = $result['encrypted_password'];
            $hash = $this->checkhashSSHA($salt, $password);
            // check for password equality
            if ($encrypted_password == $hash) {
                // user authentication details are correct
                return $result;
            }
        } else {
            // user not found
            return false;
        }
    }
 
    /**
     * Check user is existed or not
     */
    public function isUserExisted($email) {
        $result = mysql_query("SELECT email from users WHERE email = '$email'");
        $no_of_rows = mysql_num_rows($result);
        if ($no_of_rows > 0) {
            // user existed
            return true;
        } else {
            // user not existed
            return false;
        }
    }
 
    /**
     * Encrypting password
     * @param password
     * returns salt and encrypted password
     */
    public function hashSSHA($password) {
 
        $salt = sha1(rand());
        $salt = substr($salt, 0, 10);
        $encrypted = base64_encode(sha1($password . $salt, true) . $salt);
        $hash = array("salt" => $salt, "encrypted" => $encrypted);
        return $hash;
    }
 
    /**
     * Decrypting password
     * @param salt, password
     * returns hash string
     */
    public function checkhashSSHA($salt, $password) {
 
        $hash = base64_encode(sha1($password . $salt, true) . $salt);
 
        return $hash;
    }
 
}
 
?>
And here is the error log I am getting.

12-02 20:45:23.135: E/JSON(28208): <br />n<b>Warning</b>: mysql_num_rows() expects parameter 1 to be resource, boolean given in <b>/home/content/09/9443509/html/gotoclass/DB_Functions.php</b> on line <b>71</b><br />n{"tag":"register","success":0,"error":1,"error_msg":"Error occured in Registartion"}n
12-02 20:45:23.140: E/JSON Parser(28208): Error parsing data org.json.JSONException: Value <br of type java.lang.String cannot be converted to JSONObject
12-02 20:45:23.140: W/dalvikvm(28208): threadid=13: thread exiting with uncaught exception (group=0x415e62a0)
12-02 20:45:23.140: E/AndroidRuntime(28208): FATAL EXCEPTION: AsyncTask #1
12-02 20:45:23.140: E/AndroidRuntime(28208): java.lang.RuntimeException: An error occured while executing doInBackground()
12-02 20:45:23.140: E/AndroidRuntime(28208): at android.os.AsyncTask$3.done(AsyncTask.java:299)
12-02 20:45:23.140: E/AndroidRuntime(28208): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
12-02 20:45:23.140: E/AndroidRuntime(28208): at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
12-02 20:45:23.140: E/AndroidRuntime(28208): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
12-02 20:45:23.140: E/AndroidRuntime(28208): at java.util.concurrent.FutureTask.run(FutureTask.java:137)
12-02 20:45:23.140: E/AndroidRuntime(28208): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
12-02 20:45:23.140: E/AndroidRuntime(28208): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
12-02 20:45:23.140: E/AndroidRuntime(28208): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
12-02 20:45:23.140: E/AndroidRuntime(28208): at java.lang.Thread.run(Thread.java:856)
12-02 20:45:23.140: E/AndroidRuntime(28208): Caused by: java.lang.NullPointerException
12-02 20:45:23.140: E/AndroidRuntime(28208): at com.example.cs309.gotoclass.RegisterActivity$RegisterTask.doInBackground(RegisterActivity.java:89)
12-02 20:45:23.140: E/AndroidRuntime(28208): at com.example.cs309.gotoclass.RegisterActivity$RegisterTask.doInBackground(RegisterActivity.java:1)
12-02 20:45:23.140: E/AndroidRuntime(28208): at android.os.AsyncTask$2.call(AsyncTask.java:287)
12-02 20:45:23.140: E/AndroidRuntime(28208): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
12-02 20:45:23.140: E/AndroidRuntime(28208): ... 5 more
Thank you for any help you can offer!!!