如何设置swiftmail模板的路径

我尝试的是 'viewPath' => '@frontend/views/mail' . 它还在搜索 layouts/html 因为它被设置为这个文件。如何覆盖它?我试图离开 htmlLayout 属性为空,但它搜索 .../frontend/views/mail/.php . 如何禁用(如果我可以这样说) HTML布局 财产?我的代码如下:

'mailer' => [
            'class' => 'yii\swiftmailer\Mailer',
            'htmlLayout' => '',
            'viewPath' => '@frontend/views/mail',
            'transport' => [
                'class' => 'Swift_SmtpTransport',
                'host' => 'localhost',
                'username' => Yii::$app->params['adminEmail'],
                'password' => Yii::$app->params['adminEmailPass'],
                'port' => '587',
                'encryption' => 'tls',
            ],
        ],

发送邮件的方式:

Yii::$app->mailer->compose('contact',[
                'title' => 'test'
            ])
            ->setFrom(Yii::$app->params['adminEmail'])
            ->setTo($model->email)
            ->setSubject(Yii::t('app', 'Successfully sent message')." - ".Yii::$app->name)
            ->send();