Question on issuing a error message

Question

HI All,
I am new to WDA.   I am developing a WDA application, on the first view I have a table and a button to go to the next view.
When the table is empty i need to issue a error message in the message area and the user should not be able to navigate further using the NEXT button.  
I want to display this message before the user does some action i.e ( before the button trigger ).
Can some one help me how to achieve this.
Thanks,
Krishna

Answer 1

i need to issue a error message in the message area and the user should not be able to navigate further using the NEXT button.
now if ls_cn_input is INITIAL , u need to generate a error message and disable ur NEXT button
//for generating the error message
// this can be done by code wizard ( cntrl +f7) as well by selecting the radio button generate message and select the
// method *report_error_message*
*    DATA lv_message  TYPE string .
**     get message manager
*    DATA lo_api_controller     TYPE REF TO if_wd_controller.
*    DATA lo_message_manager    TYPE REF TO if_wd_message_manager.
*    lo_api_controller ?= wd_this->wd_get_api( ).
*    CALL METHOD lo_api_controller->get_message_manager
*      RECEIVING
*        message_manager = lo_message_manager .
**     report message
*    CALL METHOD lo_message_manager->report_error_message
*      EXPORTING
*        message_text   = 'Please enter data before exit .'.
// ur error message
the user should not be able to navigate further using the NEXT button.
// disable the NEXT button
u procced as follows :
1 create a context attribute of type WDY_BOOLEAN
2 bind this with ur button UI
3 nw using set_attribute method , set its value to ' ' ( ie blank)
again this cn be donr thru code wizrd by selecting read context node/attribute
DATA lo_nd_cn_node TYPE REF TO if_wd_context_node.
    DATA lo_el_cn_node TYPE REF TO if_wd_context_element.
    DATA ls_cn_node TYPE wd_this->element_cn_node .
    DATA lv_attr  LIKE ls_city-ca_attr.
*   navigate from <CONTEXT> to <CN_VISIBLE> via lead selection
    lo_nd_node = wd_context->get_child_node( name = wd_this->wdctx_ca_attr).
*   get element via lead selection
    lo_el_cn_node = lo_nd_cn_node->get_element(  ).
*   set single attribute
    lo_el_cn_node->set_attribute(
      EXPORTING
        name =  `CA_ATTR`
        value = ' '  ).
// I have read ca_attr  attribute under context node cn_node
// this attribute is binded to button UI
I hope it helps
rgds,
amit