l_object.rb - contains the Lobject class which is the base class for all Locana objects.

Author: Michael Davis, mdavis@locana.org

Copyright: (C) 2000, 2001, 2002 Seva Inc. and Seva Software - www.sevasoftware.com

Home page: www.locana.org

License: Same as Ruby

This module contains the Lobject class. Most other locana classes are based on this class. See locana.rb for more information.

Most Locana objects have many instance methods. Here are some interesting notes about instance methods for all objects in Locana. There are several major categories of methods:

• methods that operate on an object such as open() and close(). I tried to keep these to a minimum and used attributes as much as possible.
• methods that allow you to retrieve and set attributes for objects. Every attribute has a reader and writer method for accessing it directly. If these methods are not specifically defined, they are automatically created at run-time. For example: object1.value = object2.value assigns the :value attribute of object2 to the :value attribute of object1.
• methods that allow you to create, fire, and access event bindings. An event binding is basically a proc object or string that you assign to an event to be processed when an event occurs. If a method for the event has not been specifically created, one is automatically created at runtime. All event methods are prefixed with ’:on_’. For example:

     object.on_key_press = {|event| puts event} will be executed for every key_press on object
     object.on_key_press {|event| puts event} providing blocks to event also works
     object.on_key_press({:keycode=>32}) will fire the on_key_press event for object
     p = object.:on_key_press() triggers the binding for the :on_key_press event of object
     p = object[:on_key_press] will retrieve the binding for the :on_key_press event of object
  

• methods that allow you access child objects. method_missing() receives all undefined methods of all objects and if the method matches a child object, a method is automatically created allowing you to access children directing my using methods. As a result, you should be careful about how you name your objects. Using :value as the name of an object would have very undesirable effects on the object. I have a general policy of prefixing or suffixing my objects names with something like b_objectname, bObjectname, or objectname_b (where ‘b’ is the first letter of the object being created, button in this case) to make sure object names don’t interfere with Locana methods. You should do the same. For example:

     win = Lwindow.new('TestEditBox', :pos=>[60, 60, 0, 0], :text=>'Test EditBox') {
        label('l_label', :sticky=>:nw, :label=>'Type some text')
        textbox('t_text', :sticky=>:nw, :after=>:prev)
        button('b_ok', :sticky=>:se, :text => 'Ok')
        b_ok.on_click = proc {|levent| close}  # this button will close the form
        b_ok.text = 'Okay'            # changes the text in the button
     }
     win.b_ok.on_click = proc {|levent| close} # this also works
     win.b_ok.text = 'Okay'
  

• methods and instance variables used internally by locana are prefixed with ‘l_’ to reduce potential conflicts with future attributes and user defined methods.

When adding methods to new objects that you create, you will need to make sure you don’t use method names that could conflict with other locana methods or attributes including any future attributes. If you run your applet with -w or -d you should see any method redefinitions. It would be wise to review these carefully because it can tell you if you accidently replaced an locana method with one of your own.

Status

• See locana.rb

Todo

• See locana.rb

History

• See History or Versions