Merged develop branch in tutorial.

author: Joël Cox <joel@joelcox.nl> 2011-10-09 18:45:09 +0200
committer: Joël Cox <joel@joelcox.nl> 2011-10-09 18:45:09 +0200
commit: 8ffcb2c8c7ef3da54d7e46c29d502533e413c820 (patch)
tree: 1f94e2e81b4d20f2df827b8a84eeda27032161a1 /user_guide_src/source/general/views.rst
parent: f4fb1db458fab52d0493ead52c9ea7e01206eaa7 (diff)
parent: 6858c0753a7221796d6a5a1d7fea93cc2f9feb2e (diff)
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+#####
+Views
+#####
+
+A view is simply a web page, or a page fragment, like a header, footer,
+sidebar, etc. In fact, views can flexibly be embedded within other views
+(within other views, etc., etc.) if you need this type of hierarchy.
+
+Views are never called directly, they must be loaded by a
+:doc:`controller <controllers>`. Remember that in an MVC framework, the
+Controller acts as the traffic cop, so it is responsible for fetching a
+particular view. If you have not read the
+:doc:`Controllers <controllers>` page you should do so before
+continuing.
+
+Using the example controller you created in the
+:doc:`controller <controllers>` page, let's add a view to it.
+
+Creating a View
+===============
+
+Using your text editor, create a file called blogview.php, and put this
+in it::
+
+	<html>
+	<head>
+		<title>My Blog</title>
+	</head>
+	<body>
+		<h1>Welcome to my Blog!</h1>
+	</body>
+	</html>
+	
+Then save the file in your application/views/ folder.
+
+Loading a View
+==============
+
+To load a particular view file you will use the following function::
+
+	$this->load->view('name');
+
+Where name is the name of your view file. Note: The .php file extension
+does not need to be specified unless you use something other than .php.
+
+Now, open the controller file you made earlier called blog.php, and
+replace the echo statement with the view loading function::
+
+	<?php
+	class Blog extends CI_Controller {
+
+		function index()
+		{
+			$this->load->view('blogview');
+		}
+	}
+	?>
+
+If you visit your site using the URL you did earlier you should see your
+new view. The URL was similar to this::
+
+	example.com/index.php/blog/
+
+Loading multiple views
+======================
+
+CodeIgniter will intelligently handle multiple calls to
+$this->load->view from within a controller. If more than one call
+happens they will be appended together. For example, you may wish to
+have a header view, a menu view, a content view, and a footer view. That
+might look something like this::
+
+	<?php
+
+	class Page extends CI_Controller {
+
+	   function index()
+	   {
+	      $data['page_title'] = 'Your title';
+	      $this->load->view('header');
+	      $this->load->view('menu');
+	      $this->load->view('content', $data);
+	      $this->load->view('footer');
+	   }
+
+	}
+	?>
+
+In the example above, we are using "dynamically added data", which you
+will see below.
+
+Storing Views within Sub-folders
+================================
+
+Your view files can also be stored within sub-folders if you prefer that
+type of organization. When doing so you will need to include the folder
+name loading the view. Example::
+
+	$this->load->view('folder_name/file_name');
+
+Adding Dynamic Data to the View
+===============================
+
+Data is passed from the controller to the view by way of an **array** or
+an **object** in the second parameter of the view loading function. Here
+is an example using an array::
+
+	$data = array(
+	               'title' => 'My Title',
+	               'heading' => 'My Heading',
+	               'message' => 'My Message'
+	          );
+
+	$this->load->view('blogview', $data);
+
+And here's an example using an object::
+
+	$data = new Someclass();
+	$this->load->view('blogview', $data);
+
+Note: If you use an object, the class variables will be turned into
+array elements.
+
+Let's try it with your controller file. Open it add this code::
+
+	<?php
+	class Blog extends CI_Controller {
+
+		function index()
+		{
+			$data['title'] = "My Real Title";
+			$data['heading'] = "My Real Heading";
+
+			$this->load->view('blogview', $data);
+		}
+	}
+	?>
+
+Now open your view file and change the text to variables that correspond
+to the array keys in your data::
+
+	<html>
+	<head>
+		<title><?php echo $title;?></title>
+	</head>
+	<body>
+		<h1><?php echo $heading;?></h1>
+	</body>
+	</html>
+
+Then load the page at the URL you've been using and you should see the
+variables replaced.
+
+Creating Loops
+==============
+
+The data array you pass to your view files is not limited to simple
+variables. You can pass multi dimensional arrays, which can be looped to
+generate multiple rows. For example, if you pull data from your database
+it will typically be in the form of a multi-dimensional array.
+
+Here's a simple example. Add this to your controller::
+
+	<?php
+	class Blog extends CI_Controller {
+
+		function index()
+		{
+			$data['todo_list'] = array('Clean House', 'Call Mom', 'Run Errands');
+
+			$data['title'] = "My Real Title";
+			$data['heading'] = "My Real Heading";
+
+			$this->load->view('blogview', $data);
+		}
+	}
+	?>
+
+Now open your view file and create a loop::
+
+	<html>
+	<head>
+		<title><?php echo $title;?></title>
+	</head>
+	<body>
+		<h1><?php echo $heading;?></h1>
+	
+		<h3>My Todo List</h3>
+
+		<ul>
+		<?php foreach ($todo_list as $item):?>
+	
+			<li><?php echo $item;?></li>
+	
+		<?php endforeach;?>
+		</ul>
+
+	</body>
+	</html>
+
+.. note:: You'll notice that in the example above we are using PHP's
+	alternative syntax. If you are not familiar with it you can read about
+	it :doc:`here </general/alternative_php>`.
+
+Returning views as data
+=======================
+
+There is a third **optional** parameter lets you change the behavior of
+the function so that it returns data as a string rather than sending it
+to your browser. This can be useful if you want to process the data in
+some way. If you set the parameter to true (boolean) it will return
+data. The default behavior is false, which sends it to your browser.
+Remember to assign it to a variable if you want the data returned::
+
+	$string = $this->load->view('myfile', '', true);
+
author	Joël Cox <joel@joelcox.nl>	2011-10-09 18:45:09 +0200
committer	Joël Cox <joel@joelcox.nl>	2011-10-09 18:45:09 +0200
commit	8ffcb2c8c7ef3da54d7e46c29d502533e413c820 (patch)
tree	1f94e2e81b4d20f2df827b8a84eeda27032161a1 /user_guide_src/source/general/views.rst
parent	f4fb1db458fab52d0493ead52c9ea7e01206eaa7 (diff)
parent	6858c0753a7221796d6a5a1d7fea93cc2f9feb2e (diff)