Hiding Android Keyboard 'Settings' key programmatically

I want to hide the Android Keyboard Settings key programmatically. Can anyone suggest how one should approach for it. At Present I am overriding the onKeyDown() method and getting the event so that the settings event can be disabled/hidden. But this doesn't work. How can I make it possible. I need to achieve this because in my app I lock a screen and user has to enter a code to unlock it. But when he is entering the lock code through the Android soft keyboard开发者_JAVA技巧 there's this settings key through which a user can come out of the lock screen. So I need a way to hide or disable this key on the Android Soft keyboard somehow.

Any Suggestion?