登录后Yii::$app->user->isGuest的值未被改变 [ 2.0 版本 ]

登录的代码

app\models\loginform

public function login()
    {
        if ($this->validate()) {
            return Yii::$app->user->login($this->getUser(), $this->rememberMe ? 3600*24*30 : 0);
        } else {
            return false;
        }
    }

   public function getUser()
    {
        if ($this->_user === false) {
            $this->_user = User::findByUsername($this->username);
        }

        return $this->_user;
    }

app\models\user

class User extends ActiveRecord implements \yii\web\IdentityInterface
{
    public $rememberMe;
    public $username;
    public $password;


    public static function tableName()
    {
        return '{{%user}}';
    }


    public static function findIdentity($id){
        return static::findOne($id);
    }

    /**
     * @inheritdoc
     */
    public static function findIdentityByAccessToken($token, $type = null)
    {
        return static::findOne(['access_token' => $token]);
    }

    /**
     * Finds user by username
     *
     * @param  string      $username
     * @return static|null
     */
    public static function findByUsername($username)
    {
        $user = User::find()
            ->where(['UserName' => $username])
            ->asArray()
            ->one();
        if($user){
            return new static($user);
        }

        return null;
    }

    /**
     * @inheritdoc
     */
    public function getId()
    {
        return $this->UserName;
    }

    /**
     * @inheritdoc
     */
    public function getAuthKey()
    {
        return $this->authKey;
    }

    /**
     * @inheritdoc
     */
    public function validateAuthKey($authKey)
    {
        return $this->authKey === $authKey;
    }

    /**
     * Validates password
     *
     * @param  string  $password password to validate
     * @return boolean if password provided is valid for current user
     */

    public function validatePassword($password)
    {
        if($password===$password){
            return true;
        }else{
            return false;
        }
    }

    public function test(){
        $user=user::findOne(['username'=>'3color']);
        var_dump($user);
    }
}