How do I modify salt with android API for webservice development...

<?php
class DB_Functions {

private $conn;

// constructor
function __construct() {
    require_once 'DB_Connect.php';
    // connecting to database
    $db = new Db_Connect();
    $this->conn = $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

    $stmt = $this->conn->prepare("INSERT INTO users(unique_id, name, email, encrypted_password, salt, created_at) VALUES(?, ?, ?, ?, ?, NOW())");
    $stmt->bind_param("sssss", $uuid, $name, $email, $encrypted_password, $salt);
    $result = $stmt->execute();
    $stmt->close();

    // check for successful store
    if ($result) {
        $stmt = $this->conn->prepare("SELECT * FROM users WHERE email = ?");
        $stmt->bind_param("s", $email);
        $stmt->execute();
        $user = $stmt->get_result()->fetch_assoc();
        $stmt->close();

        return $user;
    } else {
        return false;
    }
}

/**
 * Get user by email and password
 */
public function getUserByEmailAndPassword($email, $password) {

    $stmt = $this->conn->prepare("SELECT * FROM users WHERE email = ?");

    $stmt->bind_param("s", $email);

    if ($stmt->execute()) {
        $user = $stmt->get_result()->fetch_assoc();
        $stmt->close();

        // verifying user password
        $salt = $user['salt'];
        $encrypted_password = $user['encrypted_password'];
        $hash = $this->checkhashSSHA($salt, $password);
        // check for password equality
        if ($encrypted_password == $hash) {
            // user authentication details are correct
            return $user;
        }
    } else {
        return NULL;
    }
}

/**
 * Check user is existed or not
 */
public function isUserExisted($email) {
    $stmt = $this->conn->prepare("SELECT email from users WHERE email = ?");

    $stmt->bind_param("s", $email);

    $stmt->execute();

    $stmt->store_result();

    if ($stmt->num_rows > 0) {
        // user existed 
        $stmt->close();
        return true;
    } else {
        // user not existed
        $stmt->close();
        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;
}
}

?>

<pre lang="PHP">else {
        $passwordTest=false ;
        //If strong password exists
        $salt=$row["passwordStrongSalt"] ;
        $passwordStrong=$row["passwordStrong"] ;
        if ($passwordStrong!="" AND $salt!="") {
            if (hash("sha256", $row["passwordStrongSalt"].$password)==$row["passwordStrong"]) {
                $passwordTest=true ;
            }
        }
        //If only weak password exists
        else if ($row["password"]!="") {
            if ($row["password"]==md5($password)) {
                $passwordTest=true ;

                //Migrate to strong password
                $salt=getSalt() ;
                $passwordStrong=hash("sha256", $salt.$password) ;

                try {
                    $dataSecure=array("passwordStrong"=> $passwordStrong, "passwordStrongSalt"=> $salt, "username"=> $username ); 
                    $sqlSecure="UPDATE gibbonPerson SET password='', passwordStrong=:passwordStrong, passwordStrongSalt=:passwordStrongSalt WHERE (username=:username)";
                    $resultSecure=$connection2->prepare($sqlSecure);
                    $resultSecure->execute($dataSecure); 
                }
                catch(PDOException $e) { 
                    $passwordTest=false ; 
                }
            }