Review: loading views sequentially with CodeIgniter - PHP

One of the most common tasks that a PHP programmer has to perform when developing web applications with CodeIgniter is loading a bunch of views to generate different sections of a web document. As with many other features provided by this framework, there are several ways to work with view files. This seven-part article series shows you many different ways to handle views. In this third part, we'll focus on nested views and other methods.

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By: Alejandro Gervasio

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April 02, 2009

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Before I proceed to demonstrate how to handle data in views via the “$this->load->vars()” method mentioned in the beginning, it would be useful to reintroduce an example developed in the preceding tutorial. As I mentioned, in that article I showed you how to build a basic web page by loading three distinct views sequentially.

Having said that, below I've listed the complete definitions of each source file that comprises the example in question. Here they are:

(definition of ‘webpage.php’ file – located at /application/controllers/ folder)

<?php

class WebPage extends Controller{

function WebPage(){

// load parent controller

parent::Controller();

// load libraries here

$this->load->database();

// load helpers here

}

// load views sequentially

function index(){

// load 'header' view

$this->load->view('header_view',array('header'=>'Header Section'));

// load 'content' view and pass database content

$this->load->view('content_view',array('users'=>$this->db->get('users')));

// load 'footer' view

$this->load->view('footer_view',array('footer'=>'Footer Section'));

}

(definition of ‘header_view.php’ file - located at /application/views/ folder)

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<head>

<title>Sample Web Page</title>

</head>

<body>

<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.</p>

</div>

(definition of ‘default.css’ file - located at /codeigniter/assets/css/ folder)

body{

padding: 0;

margin: 0;

background: #999;

}

#container{

width: 600px;

margin: 0 auto;

}

#header{

padding: 10px;

background: #eee;

}

#content{

padding: 10px;

background: #9cf;

}

#footer{

padding: 10px;

background: #eee;

}

h1{

font: bold 2em Arial, Helvetica, sans-serif;

margin: 0 0 18px 0;

color: #039;

}

h2{

font: bold 1.5em Arial, Helvetica, sans-serif;

margin: 0 0 18px 0;

}

font: normal .8em Arial, Helvetica, sans-serif;

margin: 0 0 18px 0;

}

(definition of ‘content_view.php’ file - located at /application/views/ folder)

<?php if($users->num_rows > 0):?>

<?php foreach($users->result() as $user):?>

<p><strong>First Name: </strong><?php echo $user->firstname;?></p>

<p><strong>Last Name: </strong><?php echo $user->lastname;?></p>

<p><strong>Email: </strong><?php echo $user->email;?></p>

<hr />

<?php endforeach;?>

<?php endif;?>

</div>

(definition of ‘footer_view.php’ file - located at /application/views/ folder)

</div>

</body>

</html>

In this particular case, the group of source files shown above are the building blocks of a simple CI-driven application that generates a dynamic web page by using three different views, which are loaded in a sequential way by a “WebPage” controller. Also, it’s clear to see how the controller fetches some rows from a “users” MySQL table, which are embedded into the “content_view.php” file for display purposes.

Moreover, it’s worthwhile to note here that the view responsible for building the header section of the web page also includes a separate style sheet called “default.css” for enhancing the visual appearance of the whole web document.

So far, so good. Having quickly reviewed the previous example, it’s time to see how to utilize the CI’s loader class to generate a web page similar to the one shown before. As you’ll see in a few moments, this process will require using some nested views along with the aforementioned “load->vars()” method. But to learn this topic in more detail, you’ll have to click on the link below and read the following section.

Next: Preparing a nested view for displaying database contents >>