After giving a fare bit of try i am wondering if there is a way to achieve this.
My Requirement : To show a record in the List UIBB of GAF as Display only / Read only When it has one of the columns populated with values.
To do this i am coding in GET_DATA method of the list feeder
In that , i am editing my CT_FIELD_USAGE.
LOOP AT ct_field_usage ASSIGNING <FS_FIELD_USAGE> where name = 'DESCRIPTION'.
<Fs_field_usage>-READ_ONLY = 'X'.
<Fs_field_usage>-enabled = ' '.
<Fs_field_usage>-FIXED_VALUES = lt_fixed_values.
<Fs_field_usage>-FIXED_VALUES_CHANGED = 'X'.
ev_field_usage_Changed = 'X'.
lt_fixed values is populated with the values for which my record should be "Read only".
READ TABLE lt_pre_master into ls_pre_master with KEY anlkl = ls_Assetclass_gl-anlkl.
if sy-subrc eq 0.
ls_assetclass_gl-DESCRIPTION = 'Filepath for Excelsheet'.
*Make that Asset record as read only in the List
ls_FIXED_VALUES-value = ls_assetclass_gl-DESCRIPTION."'DESCRIPTION'.
APPEND LS_FIXED_VALUES to LT_FIXED_VALUES.
Not sure if this is the correct, if not kindly guide me through the right way.