Is there any functionality baked into Android SDK that will give user visual clue that menu is available?
No.
So, any suggestions?
I consider three tiers of UI:
- The #1 point behind the activity should be accessible directly on the screen, without any menus.
- Things that somebody might want to do on the activity but are not quite as important can go in an options menu. The MENU button is always there -- users will learn to press it from time to time.
- If you have a
ListView
, and you want to have a context menu for operations on individual list items, that's cool...for power users. For ordinary people, have some more discoverable path they can take that will let them do the same things. So, for example, if a context menu offers Edit and Delete options, a simple tap on the same item should lead to an activity where the user can get to Edit and Delete options menu items.
Also, try a few different ways of offering help, in hopes that some users will, one way or another, RTFM:
- Traditional help screen (e.g., HTML in a WebView)
- Tip-of-the-day on startup
- Screencasts in the app (make them entertaining, and users will consider them "content" as much as "docs")
- Docs/screencasts on your Web site (for those who are more comfortable with long-form material on a bigger screen than their device offers)