How to disable INPUT field in Webdynpro Abap based on some Action?

I am new to ABAP Web Dynpro.

I have a Webdynpro screen, where one INPUT field is displayed in Disabled mode. Based on the user Action condition, it shourld be turned on enabled.

I went through this steps:

1. I defined a variable in the Context of the view (field_enable type wdy_boolean).

2. I made a binding for the input field with field_enable

3. I wrote the following code in the wddoinit method of the view:

DATA lo_el_context   TYPE REF TO if_wd_context_element.
DATA ls_context      TYPE wd_this->element_context.
DATA lv_field_enable TYPE wd_this->element_context-field_enable.

  lo_el_context = wd_context->get_element( ).

  lv_field_enable = abap_false.

  lo_el_context->set_attribute(
        name =  'FIELD_ENABLE'
        value = lv_field_enable ).

The problem is, when I test the application, nothing happens. What am I doing wrong?

Thanks,

Robin