Sometimes Android weirdness is really amazing (and amusing..). I solved it this way:
a) Define in XML a submenu placeholder like this:
<item android:visible="true" android:id="@+id/m_area"
android:titleCondensed="Areas"
android:title="Areas"
android:icon="@drawable/restaur"
android:enabled="true">
<menu>
<item android:id="@+id/item1" android:title="Placeholder"></item>
</menu>
</item>
b) Get sub menu item in OnCreateOptionsMenu, clear it and add my submenu items, like this:
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.mapoptions, menu);
int idx=0;
SubMenu subm = menu.getItem(MYITEM_INDEX).getSubMenu(); // get my MenuItem with placeholder submenu
subm.clear(); // delete place holder
while(true)
{
anarea = m_areas.GetArea(idx); // get a new area, return null if no more areas
if(anarea == null)
break;
subm.add(0, SUBAREASID+idx, idx, anarea.GetName()); // id is idx+ my constant
++idx;
}
}