Hello Prince,

Here you go!

**In xml file**

<button name="your_method_name" string="Button label" type="object" class="oe_hightlight"/>

** In py file**

from openerp import models,fields,api

class your_class_name(models.Model)

    _name = 'model.model'  #your model name

   #here is your method defination which you have called from xml file.

   @api.multi

    def your_method_name(self)

        #body of your method

        #here in this method you can direct access any field value for current record using self

        return True  #return True/False or as per your requrement.

Hope This will Help

Regards,

Anil.