How user app can get call when user press user button on android device?

[tvnaidu]

I have one question, if I keep one user button next to power button on android running device, this "user button" for user action, will android sends a message to application layer when user press that button? thanks


Basically I want to take some action like "packageManager.getLaunchIntentForPackage("com.and roid.browser"))" should get called when somebody press that "user button". Is Android can send event when somebody press "user button" to me, then I can call getLaunchIntentForPackage call?.

Thanks in advance.