Nrthugu

How do I put all the parent categories on one page with links to their child categories, the structure is something like this:

On the same page are all parent categories; When you click on a category, its new categories are displayed on a new page.

CategoryController:

public function actionIndex(){

    return $this->render('index', [

        'model' => $this->outTree($id)

    ]);

}



public function getAllArray(){

    $all = Category::find()->all();

    $array = array();

    foreach($all as $v){

        $array[$v->parentId] = $v;

    }

    return $array;

}



public function outTree($parentId) {

    $array = $this->getAllArray();

    if(isset($array[$parentId])){

        echo '<div>';

        foreach($array[$parentId] as $v){

            echo '<div>'.$v->name.'</div>';

            echo '<div>'.$v->id.'</div>';

            echo '<div>'.$v->parentId.'</div>';

            $this->outTree($v->id);

        }

        echo '</div>';

    }

} 



protected function findModel($alias)

{

    if (($model = Category::findOne(['alias' => $alias, 'active' => 1])) !== null) {

        return $model;

    } else {

        throw new NotFoundHttpException('The requested page does not exist.');

    }

}

Relationship of parent categories with children:

public function getParent()

{

    return $this->hasOne(Category::className(), ['id' => 'parentId']);

}

How do I make such a conclusion in the view, now the output goes in the controller? At the moment, all parent categories and their child categories are displayed on the same page. Do I need to register something in UrlManager?

You can do it by this:

Your Controller:

public function actionIndex($parentId = null){

    $models = Category::find()->andWhere(['parent_id' => $parentId])->all();



    return $this->render('index', [

        'models' => $models

    ]);

}



public function actionGetChilds($parentId){

        $models = Children::find()->andWhere(['parent_id' => $parentId])->all();



        return $this->render('childs', [

            'models' => $models

        ]);

    }

You View Page(index):

foreach($models as $model): 

    echo Html::a($model->name, Url::to(['index', 'parentId' => $model->parent_id]));

endforeach;

Your View Page(child):

foreach($models as $model): 

    echo Html::a($model->name, Url::to(['get-childs', 'parentId' => $model->parent_id]));

endforeach;

Note: I think you another relation with name GetChildern in Category
Model, you can use it in index action to get all child for category by
this $model->childern