Questions about Android Menu key

The recent development of the need for the menu key, the results found a very embarrassing problem. I have the menu key on my test machine. But the test plate did not, the teammate's test machine even there is no menu button. This is a bit embarrassing ...

Google after the internet only to find the problem:

There is only inandroid 4.0 before the machine, the menu key is only as a hardware exists, after the machine has. There is no, for example, Samsung's S3,note2 and so on have this button. But many other phones have canceled the button. So assuming that project is useful to this key, you must lower the minimum version number,  , for example, the Android 2.2 project, ran to 4.0 of the machine (4.0 has canceled the hardware menu). Then it will cause menu key missing On the virtual menu key.

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       so the key point in the manifest file: <uses-sdk android:minsdkversion="/> ", suppose you support 4.0 to

Before the version number, you will be added to the virtual menu.

at this point at the top of each activity. More than a Virtual menu key, every time you click on the screen it will appear first. in the Systemui. It's the first one to pick up

The event that was clicked.

let's say your minimum version number is support 4.0. Then Google will feel that you already know about such hardware changes. Brought by the software

The difference is that you have to handle the problem of the menu cancellation in the program yourself. He will not be mandatory for you to add virtual menu.
    

Questions about Android Menu key