注意：试图获取非对象的属性

Question

我仍在关注 login/register 教程我已经看了几次视频，看看我是否在某个地方犯了打字错误，但我似乎找不到任何错误得到的是 "Notice: Trying to get property of non-object"

我确实环顾四周，建议尝试以下解决方案，但它没有用：

echo $user[0]->data()->username;

我知道这与我的数据有关 class，嗯，我认为是我的数据 class 错了。

index.php

  <?php
        require_once 'core/init.php';

    if(Session::exists('home')){
        echo '<p>' . Session::flash('home', 'You have been registered and can now log in!') . '</p>';
    }

    $user = new User();
    echo $user->data()->username;
    ?>


    <a href="login.php">Login</a>

User.php

 <?php
    class User{
        private $_db,
                $_data,
                $_sessionName;

        public function __construct($user = null){
            $this ->_db = DB::getInstance();

            $this->_sessionName = Config::get('session/session_name');

        if(!$user){
            if(Session::exists($this->_sessionName)){
                $user = Session::get($this->_sessionName);

            if($this->find($user)){
                $this->_isLoggedIn = true;
                    }else{
                        //logout 
                    }
                }
            } else{
                $this->find($user);
            }
        }


        public function create($fields = array()){
            if($this->_db->insert('users', $fields)){
                throw new Exception('There was a problem creating account');
            }
        }

        public function find($user = null){
            if($user){
                $field = (is_numeric($user)) ? 'id' : 'username';
                $data = $this->_db->get('users', array($field, '=', $user));

                if($data->count()) {
                    $this->_data = $data->first();
                    return true;
                }
            }
            return false;
        }
        public function login($username = null, $password = null){
                $user = $this->find($username);

            if($user){
                if($this->data()->password ===Hash::make($password, $this->data()->salt)){
                    Session::put($this->_sessionName, $this->data()->id);
                    return true;
                }
            }       
            return false;
        }

        public function data(){
            return $this->_data;
        }

    }

Login.php

<?php
require_once 'core/init.php';

if(Input::exists()){
    if(Token::check(Input::get('token'))){

        $validate = new Validate();
        $validation = $validate->check($_POST, array(
            'username' => array('required' => true),
            'password' => array('required' => true)
        ));

        if ($validation->passed()){
            //log user in
            $user = new User();
            $login = $user->login(Input::get('username'), Input::get('password'));

            if($login){
                echo 'Success';


            }else{
                echo'<p>Sorry invalid details</p>';
            }
        } else{
            foreach($validation->errors() as $error)
                echo $error, '<br />';
        }
    }
}

?>
<form action="" method="POST">
    <div class="field">
        <label for="username" id="username"> Username </label>
        <input type="text" name="username" id="username" autocomplete="off">
    </div>

    <div class="field">
        <label for="password" id="password"> Password </label>
        <input type="password" name="password" id="password" autocomplete="off">
    </div>
    <input type="hidden" name="token" value="<?php echo Token::generate();?>">
    <input type="submit" value="Login">
</form> 

<a href ="index.php">Home</a>

Session.php

<?php
class Session {
    public static function put($name, $value){
        return @$_SESSION[$name] = $value;
    }
    public static function get($name)
    {
        return self::exists($name) ? @$_SESSION[$name] : null;
    }
    public static function exists($name)
    {
        return @$_SESSION[$name] !== null;
    }
    public static function delete($name){
        if(self::exists($name)){
            unset($_SESSION[$name]);
        }
    }

    public static function flash($name, $string =''){
        if(self::exists($name)){
            $session = self::get($name);
            self::delete($name);
            return $session;
        } else {
            self::put($name, $string);
        }
    }
}

Answer 1

我假设这是有问题的代码：

$user = new User();
echo $user->data()->username;

此代码实例化了一个 User 对象，我们可以看到构造函数需要提供用户名（或可能是 id？）。如果没有给出用户名，查找函数看起来只是 returns false，因此数据数组将为空。这就是您收到错误消息的原因。

尝试使用当前用户名调用构造函数，例如

$user = new User('test');

如果索引页面可以在没有用户名的情况下加载，那么您只需要在尝试使用它之前对数据对象添加额外的检查，例如

if (@$user->data())    
    echo $user->data()->username;
else
    echo "Not logged in";

Answer 2

我的 init.php 文件中的基本打字错误，我真的很讨厌自己...