Unable to Edit the View in Custom Component

Question

Hi Experts,
Please help me to resolve this issue !
I am unable to lock the BOL Entity in my custom component using BTAdminH. I have written the below code in the Edit event Handler for Edit Button. The lr_entity->lock( ) condition statement is getting false and it is skipping the "set_view_editable( me )." code statement. Why??
This is code excerpt that I have taken from edit button of the BP_HEAD/AccountViewSet and altered to my component/View
DATA: lr_entity     TYPE REF TO cl_crm_bol_entity,
        lr_controller TYPE REF TO cl_ZVKH8_bspwdcomponent_impl.
  TRY.
      lr_controller ?= me->comp_controller.
      lr_entity ?= lr_controller->typed_context->btadminh->collection_wrapper->get_current( ).
IF lr_entity IS BOUND.
  IF lr_entity->IS_LOCKED EQ abap_false.
    IF le_entity->IS_CHANGEABLE EQ abap_true.
       IF lr_entity->lock( ) EQ abap_true.
        me->view_group_context->set_view_editable( me ).
       ENDIF.
    ENDIF.
  ENDIF.
ENDIF.
and when I directly executed the below code in the Edit event Handler for Edit Button I am receiving the dereferencing NULL value exception. Why in my custom component in many places this happening??
  me->view_group_context->set_view_editable( me ).
Exception Details
CX_SY_REF_IS_INITIAL - Dereferencing of the NULL reference
Method: ZL_ZVKH8_DETAILSEF_IMPL=>EH_ONBACK
Thanks,
Bujji

Answer 1

Hi Summit & NishaNC,
Thanks for your responses !
As suggested, I have debugged the code for ->lock( ) method and there are exceptions raised from some methods.
Method GET_LOCK () -> Method GET_ROOT () ->Method GET_PARENT ()
At GET_ROOT( ) method i have received an exception
"Root entity BTAdminH could not be determined" and one more "Entity BTAdminH could not be locked"
Later when I have checked in MODEL Browser, I found that the BOL object "BTAdminH" for my view is an Access object and not the Root Object.
Hence, I have a question? Does the locking can be done only for ROOT Objects?
If this is TRUE then I think this is the major problem with my custom component where even the cross component navigation is also not happening and in many places I am receiving "Dereferencing NULL Value" information.
Also I have gone through some of the Threads and one information that I found from Sumit Mittal
1. An access object is an independent entity, has primary keys of its own.
2. A root object is a special access object that is at the top of the hierarchy based on business rules.
3. A dependent object's primary keys are supplied by access objects and it's lifetime is bound to them. If the parent object is destroyed, the dependent object is also destroyed.
4. Search objects are query objects useful for querying root objects
5. Search result objects - Search objects return the results in the form of a result object together with a relation pointing to the root object.
6. View objects - ?
7. Dynamic search objects - Used in advanced search, supports ranges and operators
Could you please specify in which scenarios we have to go for Access Objects and Root Objects
Thanks,
Bujji