Ruby on Rails 2.1 - Layouts


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A layout defines the surroundings of an HTML page. It's the place to define the common look and feel of your final output. Layout files reside in app/views/layouts.

The process involves defining a layout template and then letting the controller know that it exists and is available for use. First, let's create the template.

Add a new file called standard.rhtml to app/views/layouts. You let the controllers know what template to use by the name of the file, so following a same naming same is advised.

Add the following code to the new standard.rhtml file and save your changes −

<!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>    
      <meta http-equiv="Content-Type" content="text/html;.
         charset=iso-8859-1" />
      
      <meta http-equiv="Content-Language" content="en-us" />
      
      <title>Library Info System</title>
      
      <%= stylesheet_link_tag "style" %>
   </head>
	
   <body id="library">
      
      <div id="container">
         
         <div id="header">
            <h1>Library Info System</h1>
            <h3>Library powered by Ruby on Rails</h3>
         </div>
			
         <div id="content">
            <%= yield -%>
         </div>
			
         <div id="sidebar"></div>
      
      </div>
   
   </body>
</html>

Everything you just added are standard HTML elements except the two lines with the stylesheet_link_tag helper method that outputs a stylesheet <link>. In this instance, we are linking the style.css stylesheet. The yield command lets Rails know that it should put the RHTML for the method called here.

Now open book_controller.rb and add the following line just below the first line −

class BookController < ApplicationController
   layout 'standard'
   def list
      @books = Book.find(:all)
   end
...................

It directs the controller that we want to use a layout available in the standard.rhtml file. Now, try browsing books that will produce the following screen.

Layout Example

Adding a Stylesheet

Till now, we have not created any stylesheet, so Rails is using the default stylesheet. Now, let's create a new file called style.css and save it in /public/stylesheets. Add the following code to this file.

body {
   font-family: Helvetica, Geneva, Arial, sans-serif;
   font-size: small;
   font-color: #000;
   background-color: #fff;
}
a:link, a:active, a:visited {
   color: #CD0000;
}
input { 
   margin-bottom: 5px;
}
p { 
   line-height: 150%;
}
div#container {
   width: 760px;
   margin: 0 auto;
}
div#header {
   text-align: center;
   padding-bottom: 15px;
}
div#content {
   float: left;
   width: 450px;
   padding: 10px;
}
div#content h3 {
   margin-top: 15px;
}
ul#books {
   list-style-type: none;
}
ul#books li {
   line-height: 140%;
}
div#sidebar {
   width: 200px;
   margin-left: 480px;
}
ul#subjects {
   width: 700px;
   text-align: center;
   padding: 5px;
   background-color: #ececec;
   border: 1px solid #ccc;
   margin-bottom: 20px;
}
ul#subjects li {
   display: inline;
   padding-left: 5px;
}

Now, refresh your browser and see the difference −

Layout Example

What is Next?

The next chapter explains how to develop applications with Rails Scaffolding to give user access to add, delete, and modify the records in any database.



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