Android Studio: Is it possible to trigger hardware menu button

Question

I have an android application which kind of like a home screen of the build-in screen on android phone. I can list all the available applications and run them. One thing I don't know how to do is when user run an application from my apps, my application can trigger the hardware menu button to show the current application menus.

Is this possible ? If not, what about doing it if the device was rooted.

Answer 1

In activity use override onKeyDown like this :

@Override
public boolean onKeyDown(int keycode, KeyEvent e) {
    switch(keycode) {
        case KeyEvent.KEYCODE_MENU:
            doSomething();
            return true;
    }

    return super.onKeyDown(keycode, e);
}

Answer 2

In order to open up the menu from other application apart from the caller application, the device have to be rooted before the code to work.