A view is a page template, usually named after an action. For example, the view for PostsController::add() would be found at /app/views/posts/add.thtml. Cake views are quite simply PHP files, so you can use any PHP code inside them. Although most of your view files will contain HTML, a view could be any perspective on a certain set of data, be it XML, and image, etc.
In the view template file, you can use the data from the corresponding Model. This data is passed as an array called $data. Any data that you've handed to the view using set() in the controller is also now available in your view.
The HTML helper is available in every view by default, and is by far the most commonly used helper in views. It is very helpful in creating forms, including scripts and media, linking and aiding in data validation. Please see section 1.1 in Chapter 9 for a discussion on the HTML helper.
Most of the functions available in the views are provided by Helpers. Cake comes with a great set of helpers (discussed in Chapter 9), and you can also include your own. Because views shouldn't contain much logic, there aren't many well used public functions in the view class. One that is helpful is renderElement(), which will be discussed in section 1.2.
A layout contains all the presentational code that wraps around a view. Anything you want to see in all of your views should be placed in your layout.
Layout files are placed in /app/views/layouts. Cake's default layout can be overridden by placing a new default layout at /app/views/layouts/default.thtml. Once a new default layout has been created, controller view code is placed inside of the default layout when the page is rendered.
When you create a layout, you need to tell Cake where to place your controller view code: to do so, make sure your layout includes a place for $content_for_layout (and optionally, $title_for_layout). Here's an example of what a default layout might look like:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title><?php echo $title_for_layout?></title>
<link rel="shortcut icon" href="favicon.ico" type="image/x-icon">
<body>
<!-- IF you'd like some sort of menu to show up on all of your views, include it here -->
<div id="header">
<div id="menu">...</div>
</div>
<!-- Here's where I want my views to be displayed -->
<?php echo $content_for_layout ?>
<!-- Add a footer to each displayed page -->
<div id="footer">...</div>
</body>
</html>
You can create as many layouts as you wish for your Cake site, just place them in the app/views/layouts directory, and switch between them inside of your controller actions using the controller's $layout variable, or setLayout() function.
For example, if a section of my site included a smaller ad banner space, I might create a new layout with the smaller advertising space and specify it as the layout for all controller's actions using something like:
var $layout = 'default_small_ad';
Many applications have small blocks of presentational code that needs to be repeated from page to page, sometimes in different places in the layout. Cake can help you repeat parts of your website that need to be reused. These reusable parts are called Elements. Ads, help boxes, navigational controls, extra menus, and callouts are often implemented in Cake as elements. An Element is basically a mini-view that can be included in other Views.
Elements live in the /app/views/elements/ folder, and have the .thtml filename extension.
The Element by default has no access to any data. To give it access to data, you send it in as a named parameter in an array.
Example 8.2. Calling an Element passing a data array
<?php echo $this->renderElement('helpbox', array ( "helptext" => "Oh, this text is very helpful." ) ); ?>Inside the Element file, all the passed variables are available as the names of the keys of the passed array (much like how set() in the controller works with the views). In the above example, the /app/views/elements/helpbox.thtml file can use the $helptext variable. Of course, it would be more useful to pass an array to the Element.
Elements can be used to make a View more readable, placing the rendering of repeating elements in its own file. They can also help you re-use content fragments in your website.