A Cookbook.

Every cookbook needs a Hello world recipe. I won’t omit this.

We will write the first small widget here. It will plug into the application and show the magic words. As widgets are derived cells, widgets that contain user application logic are called Cell in Apotomo.

app/cells/hello_world_cell.rb

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class HelloWorldCell < Apotomo::StatefulWidget
  def say_hello
    "Hello world!"
  end
end

Note that our fresh cell widget is derived from Apotomo::StatefulWidget, which is the superclass of any widget.

So, how do we plug that widget into our application? In Apotomo, widgets are organized in a widget tree. The initial widget tree is defined in a well-known ruby class file.

app/apotomo/application_widget_tree.rb

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class ApplicationWidgetTree < Apotomo::WidgetTree
  def draw(root)
    root << cell(:hello_world, :say_hello, 'hello_world_cell')
  end
end

By using the method cell, we advise Apotomo to render the widget HelloWorldCell and its state say_hello. A state is mapped to a method that itself returns the state view.
The third argument is an id string - it’s needed when referencing to that widget.

To push the widget in the actual application we have to go into a controller method.

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class SomeController < ApplicationController  
  include Apotomo::ControllerHelper
 
  def top
    act_as_widget('hello_world_cell')
  end
end

The method act_as_widget plugs in our handsome widget. In the end, when navigating to some_controller/top, you will see the string “Hello world!”. Wow, this is awesome. Congratulations to your first widget.

Tags: cells, widget tree

This entry was posted on Tuesday, April 22nd, 2008 at 10:04 pm and is filed under Cookbook, Introduction. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.