动态更改选项菜单，但通过从XML中充气。

i need to be able to change the options menu (the one that is shown upon pressing the menu button) on android , so that on one case (for example upon a button being pressed) , it will use a specific menu resource (XML file as in /res/menu/... ) for the menu , and on another case , use a different XML file.i need to be able to change the options menu (t