Yii2使用数据库创建动态导航

Question

I'm implementing a dynamic navbar in Yii2 which displays a dropdown menu picking items from the database. Now, the problem is that when I call the function in which I fill the array, the system crash with the error:

"Invalid argument supplied for foreach()"

since it doesn't find the variable with the array of items. I don't know which controller should pass the arguments to the main view, I just need an array of all items in a data model (i.e. Course).

I've tried out with this but still doesn't work.

  /* @var $courses \app\models\Course[] */

layouts/main

function items($courses)
{
    $items = [];
    foreach ($courses as $course) {
        array_push($items, ['label' => $course->title, 'url' => 
        Url::to(['course', 'id' => $course->id])]);
    }
    return $items;
}

$menuItems = [
// other items ...
    'label' => 'Courses', 'items' => items($courses)
];

echo Nav::widget([
    'options' => ['class' => 'uk-navbar-item'],
    'encodeLabels' => false,
    'items' => $menuItems
 ]);

How can I pass the $courses variable to the layouts/main view? Thanks everyone in advance.

Answer 1

You should extract this code into widget:

class MainMenu extends Widget {

    public function run() {
        echo Nav::widget([
            'options' => ['class' => 'uk-navbar-item'],
            'encodeLabels' => false,
            'items' => $this->getItems(),
        ]);
    }

    protected function getItems() {
        return [
            // other items ...
            ['label' => 'Courses', 'items' => $this->getCoursesItems()],
        ];
    }

    protected function getCoursesItems() {
        $items = [];
        foreach (Course::find()->all() as $course) {
            $items[] = [
                'label' => $course->title,
                'url' => Url::to(['/course', 'id' => $course->id]),
            ];
        }
        return $items;
    }
}

Then in your layout you're just calling:

<?= MainMenu::widget() ?>

In this way you can keep your controller and view clean.