Ok,try following code.

import appuifw

items = [(u"aaaaaaaaaaaa",u"aaaaaaaaaaaaa"),(u"bbbbbbbbbbbb",u"bbbbbbbbbbbbb"),(u"cccccccccccc",u"ccccccccccccc")]
...

The project here. http://sdrv.ms/VdUINw

I recompile the project and modify the default.py to another script with secondary menu, but when I open the secondary menu, it exits immediately !

Why do you need to show so many characters. After all,the width of phone screen is limited.
Maybe you can modify the appuifw module with carbide c++ to solve it.