OpenCart render front-end - templates

Question

Hy all,
I'm trying to give users an confirmation message when they unsubscribe to an newsletter. But i'm only getting the confirmation message without the rest of the website.
Here's the url so you can see what's going on...
In the unsubscribe controller class i have this code to render the page:
$this->language->load('newsletter/unsubscribe');
$this->data['heading_title'] = $this->language->get('heading_title');
$this->data['breadcrumbs'] = array();
$this->data['breadcrumbs'][] = array(
'text' => $this->language->get('text_home'),
'href' => $this->url->link('common/home'),
'separator' => false
);
$this->template = 'default/template/newsletter/newsletter.tpl';
$this->children = array(
'common/column_left',
'common/column_right',
'common/content_top',
'common/content_bottom',
'common/footer',
'common/header'
);
$this->response->setOutput($this->render());
My template file looks like this:
<div class="box">
<div class="box-heading">Uitschrijven</div>
<div class="box-content">
<div id="notification">
<div class="success" style="">
U bent succesvol uitgeschreven.
<img src="catalog/view/theme/metroshop/image/close.png" alt="" class="close">
</div>
</div>
</div>
</div>
When i look at the other's ( the product controller or the account, and google ) it says that this is the right way to render the page ( with the childs like that ). But as you can see, the children ( the rest of the site ) isn't renderd.
What did i miss? Why isn't this working?

Answer 1

Alright, i've figured it out. I could delete my question, but mayby does this help others in the future so i'm answering it...
My template file looked like this:
<div class="box">
<div class="box-heading">Uitschrijven</div>
<div class="box-content">
<div id="notification">
<div class="success" style="">
U bent succesvol uitgeschreven.
<img src="catalog/view/theme/metroshop/image/close.png" alt="" class="close">
</div>
</div>
</div>
</div>
That's only the content. But you also need to echo the header, footer and all that kind of stuff. So you've got to do something like thisedi:
<?php echo $header; ?>
<?php echo $column_left; ?>
<?php echo $column_right; ?>
<div id="content">
<?php echo $content_top; ?>
<h1 style="display: none;">
<?php echo $heading_title; ?>
</h1>
<div class="box">
<div class="box-heading">Uitschrijven</div>
<div class="box-content">
<div id="notification">
<div class="success" style="">
U bent succesvol uitgeschreven.
<img src="catalog/view/theme/metroshop/image/close.png" alt="" class="close">
</div>
</div>
</div>
</div>
<?php echo $content_bottom; ?>
</div>
<?php echo $footer; ?>
And that's working fine now. Hope that this help's somebody in the future.