Yii2 advanced change views default path (theming)

Question

I would like for my application to automatically change template so i created this structure frontend/web/themes/myTheme
following http://www.yiiframework.com/doc-2.0/guide-output-theming.html i added this code in frontend/config/main.php

    'components' => [
        'view' => [
            'theme' => [
                'basePath' => '@app/themes/myTheme',
                'baseUrl' => '@web/themes/myTheme',
                'pathMap' => [
                    '@app/views' => '@app/themes/myTheme',
                ],
            ],
        ],
    ],

however i kept getting the error that " /var/www/html/myProject/app/frontend/views/site/index.php" The view file does not exist???

i also tried to put this function inside the controller based on How to change default view path in Yii2?

public function getViewPath()
{
    return Yii::getAlias('@web/themes/myTheme/site');
}

so my question is: 1. how can I change the views default path? 2. how can i do it automatically since i can not change the common/config/main.php settings during a session?

site controller

class SiteController extends Controller
{
    public function behaviors()
    {
        return [
            'access' => [
                'class' => AccessControl::className(),
                'rules' => [
                    [
                        'actions' => ['index'],
                        'allow' => true,
                        'roles' => ['?'],
                    ],
                    [
                        'actions' => ['index'],
                        'allow' => true,
                        'roles' => ['@'],
                    ],
                ],
            ],
        ];
    }
    public function actions()
    {
        return [
            'error' => [
                'class' => 'yii\web\ErrorAction',
            ],
            'captcha' => [
                'class' => 'yii\captcha\CaptchaAction',
                'fixedVerifyCode' => YII_ENV_TEST ? 'testme' : null,
            ],
        ];
    }

    /**
     * Displays homepage.
     *
     * @return mixed
     */
    public function actionIndex()
    {
        $searchModel = new ProductSearch();
        $dataProvider = $searchModel->search(Yii::$app->request->queryParams);

        return $this->render('index', [
            'searchModel' => $searchModel,
            'dataProvider' => $dataProvider,
        ]);
    }
}

Answer 1

First question:

I think than you have a common mistake in yii when used advanced app: the alias @app references root directory of frontend, backend, or common depending on where you access it from View documentation here. You would used the solution proposed by ovicko.

Second question:

You can change the theme configuration dynamically in controller through view object:

 $this->view->theme->pathMap =['@app/views' => '@app/themes/myTheme/',]; 

EDIT According to Documentation:

Theming is a way to replace a set of views with another without the need of touching the original view rendering code.

What means that the original view file must exist and theming simply replace it in during rendering. So you must create a file in /var/www/html/myProject/app/frontend/views/site/index.php (a empty file is valid) in order to theming works. This sounds quite ridiculous, I Know, but it works.

But I think that is much better and easier the use of differents layouts, again, to change dinamically the layout in your controller:

 $this->layout = 'route/yourlayout';

Answer 2

I think you are configuring the wrong file.Don't configure themes in the common/config Try this: in frontend/config/main.php

'components' => [
        'view' => [
            'theme' => [
                'pathMap' => [
                    '@frontend/views'=>'@frontend/themes/myTheme',
                ],
            ],
        ],
    ],

if you need to configure the backend then in the backend/config/main.php

'components' => [
            'view' => [
                'theme' => [
                    'pathMap' => [
                        '@backend/views'=>'@backend/themes/myTheme',
                    ],
                ],
            ],
        ],

The common folder is has to contain the files that are required by both frontend and backend. Hope this helps.