CakePHP3：admin用のレイアウト

レイアウトの作成

mkdir -p app/src/Template/Admin/Layout
cp app/src/Template/Layout/default.ctp app/src/Template/Admin/Layout/admin.ctp

AppControlllerを編集し、prefixに応じてlayoutを選択

src/Controller/AppController.php

    public function beforeRender(Event $event)
    {
        // 以下の5行を追加
        if ($this->request->param('prefix') === 'admin') {
          $this->viewBuilder()->layout('admin');
        } else {
          $this->viewBuilder()->layout('default');
        }
        if (!array_key_exists('_serialize', $this->viewVars) &&
            in_array($this->response->type(), ['application/json', 'application/xml'])
        ) {
            $this->set('_serialize', true);
        }
    }