Odoo/OpenERP : Call function on button

There are three ways to add functionality on button in OpenERP/Odoo:

1. Call function directly on button: You can directly call the function defined in model/class using type="object" attribute.

i.e

<button string="Check availability" name="check_username_availability" type="object" class="oe_highlight" />

In this case you have to define 'check_username_availablilty' function in model.

2. Using Workflow: Workflow is the most used functionality in OpenERP/Odoo to process flow of the activity. Default type of button is workflow i.e type="workflow".  Workflow itself is an vital topic so can't talk much about this here.

<button string="Accept" name="signal_accept" type="workflow" class="oe_highlight" />

3. Using action: You have to user type="action" if you want to call any action defined in the .xml file. For example if you want to open any wizard you can use following code snippet:

<button name="%(action_id)d" string="Button Label" type="action">

or you can replace %(action_id)d with action id from database.

Reference Links:

http://stackoverflow.com/questions/17462992/how-to-add-simple-func-to-a-button-in-openerp-7

http://stackoverflow.com/questions/14682253/name-of-type-action-in-openerp-button

Thanks!!!!!!!!!! Enjoy Programming :)