In my Samsung Galaxy S long-press home button open the stock/samsung task manager. Is there any way to programmatically change the asociated action for this event? I suppose it will not depend on the device, as it looks like an android issue in general. Would like to put another custom task manager
Also I have been looking in the android market for an application that do that, but dont find it, which sounds strange. (there are lot for changing the simple-touch home button action) though.
Post ICS i.e. Android 4+, the overriding of the HomeButton has been removed for security reasons, to enable the user exit in case the application turns out to be a malware.
Plus, it is not a really good practice to not let the user navigate away from the application. But, since you are making a lock screen application, what you can do is declare the activity as a Launcher , so that when the HomeButton is pressed it will simply restart your application and remain there itself (the users would notice nothing but a slight flicker in the screen).
EDIT #1 : Here is another workaround, more suited to your needs.
EDIT #2 : Came across this. Haven't tested it. But looks kinda promising. Not sure if it would work, but you could give it a try.
Android will not allow you to do custom actions on pressing Home Button event. :)
There are apps in the play store that allow you to customise the button such as Home2 Shortcut.
https://play.google.com/store/apps/details?id=com.eikatou0.appspot.home2shortcut
