Are the physical buttons that Android phones come with standard? Specifically the back, menu, home, and search button? In my applications I assume everyone has a back button so I don't bother putting in a "soft" button to go back to a previous screen.
For some reason I can't find any official documentation on this.
Looking at http://www.androphones.com/2010-android-phones.php it appears that all of the phones have at least the back, menu and home button.
Should I just assume all phones have a back button or do I have to always code one in my apps?
The CDD describes what is required to be compatible:
http://source.android.com/compatibility/index.html
(See "Current CDD" on the left)
In this case:
7.2.3. Navigation keys
The Home, Menu and Back functions are essential to the Android navigation paradigm. Device implementations MUST make these functions available to the user at all times when running applications. These functions MAY be implemented via dedicated physical buttons (such as mechanical or capacitive touch buttons), or MAY be implemented using dedicated software keys, gestures, touch panel, etc.Android 4.1 supports both implementations