Hi Kranthi,
You can use buttons if_wd_window=>co_buttons_okcancel.
Please modify your code as below
lr_window = lr_window_manager->create_window(
window_name = 'INVOICES_WIN'
message_display_mode = if_wd_window=>co_msg_display_mode_selected
button_kind = if_wd_window=>co_buttons_okcancel
message_type = if_wd_window=>co_msg_type_none
default_button = if_wd_window=>co_button_ok
).
lr_view_controller = wd_this->wd_get_api( ).
CALL METHOD lo_window->subscribe_to_button_event " register event before opening window
EXPORTING
button = if_wd_window=>co_button_ok
title = 'SUBMIT'
action_name = 'OK' " You have to create action OK in Actions tab & write req handling
action_view = lr_view_controller.
Create another action "REJECT" in your view and subscribe the cancel button to the action
CALL METHOD lo_window->subscribe_to_button_event " register event before opening window
EXPORTING
button = if_wd_window=>co_button_cancel
title = 'Reject'
action_name = 'REJECT' "create action "REJECT"
action_view = lr_view_controller.
There are different set of buttons available in IF_WD_WINDOW and you can make use of them
Hope this helps you.
Regards,
Rama