Add Title(heading) to ALV Grid

非HTML的表頭,這樣的表頭可以預覽下載的,但是HTML格式的似乎是不行 

In order to insert a report heading in to the ALV grid you need to perform the following steps:
               1. Update 'REUSE_ALV_GRID_DISPLAY' FM call to include 'top-of-page' FORM
           2. Create 'top-of-page' FORM