The definition of breadcrumbs according to its documentation is as follow: Breadcrumbs displays a list of links indicating the position of the current page in the whole site hierarchy.

We can define the breadcrumbs easily by adding these lines.

$this->title = $model->formNo;
$this->params['breadcrumbs'][] = ['label' => Yii::t('app', 'Supplier receiving'), 'url' => ['index', 'type' => $model->type]];
$this->params['breadcrumbs'][] = ['label' => $this->title, 'url' => ['view', 'id' => $model->id]];

Reading the documentation, I encountered the template keyword. I was excited about the possibility to add buttons into breadcrumbs. Add these lines and you would have buttons on the right side of the breadcrumb.

$this->title = $model->formNo;
$this->params['breadcrumbs'][] = ['label' => Yii::t('app', 'Supplier receiving'), 'url' => ['index', 'type' => $model->type]];
$this->params['breadcrumbs'][] = ['label' => $this->title, 'url' => ['view', 'id' => $model->id]];
$this->params['breadcrumbs'][] = ['label' => Yii::t('app', 'Delete'), 'template' =>
    Html::tag('span', Html::a(Html::icon('glyphicon glyphicon-trash white') . ' ' . Yii::t('app', 'Delete'), Url::to(['delete', 'id' => $model->id]), [
                'class' => 'btn btn-xs btn-danger',
                'title' => Yii::t('app', 'Delete'),
                'data-pjax' => '0',
                'data-method' => 'POST',
                'data-confirm' => Yii::t('app', 'Are you sure you want to delete this supplier receiving?'),
                    ]
            ), ['class' => 'pull-right'])];
$this->params['breadcrumbs'][] = ['label' => Yii::t('app', 'Update'), 'template' => Html::tag('span', Html::a(
                    Html::icon('glyphicon glyphicon-pencil') . ' ' . Yii::t('app', 'Update'), Url::to(['update', 'id' => $model->id, 'inview' => 1]), [
                'class' => 'btn btn-xs btn-warning',
                'title' => Yii::t('app', 'Update'),
                'role' => 'modal-remote',
                'data-toggle' => 'tooltip',
                    ]
            ), ['class' => 'pull-right', 'style' => 'margin-right: 5px;'])];

Actually you can use this line to define the template, but $links means the full link. A suggestion to the developer is to make the $url and $label variables to be available like $links, so that we can make the template more flexible and meaningful than above codes.

FYI,

1. I use ajaxcrud extension, so that the update link has 'role' => 'modal-remote' to allow the update process taken place on the modal window. I added a inview parameter to distinguish the update from index or view. Both actions will be called using ajax request and will show the form on the modal, but the index update will redirect to index and refresh gridview while in the view, it should redirect to the view.
2. On the template, I used span over li to make ' / ' character not appear on the links buttons.

A simple tip to make the view layout efficient.