Android small class (library) that implements home button 'lock'.

This is an implementation for an android kids app that wants to provide a way of locking the home key temporarily while the app runs. It must run and work on 2.2+ (2.2 up to and including the current latest version 4.1) but if it can be done for earlier levels thats even better. I need someone that can do it and do it fast. For the selected candidate : this is a task that you did before or have a good knowledge of how to do, fast. No hacks or security overrides! Use case : the user clicks on a 'child lock' button and is presented with a dialog that shows an image [explaining the user graphically what he must do in the next step] and an 'ok' and 'cancel' button. On pressing 'cancel' the dialog closes and operation resumes as before the dialog was opened. On pressing 'ok' he is presented with a choice [from the android system] to select his home screen which contains the current app. On app exit the home screen is restore to its previous state. The API should look something like this : public class ChildLock { /** the image that graphically explains to the user how to select the app as a default home screen */ private Bitmap image; public ChildLock(Bitmap image) { [login to view URL] = image; } /** starts and completes the process of giving the info/options to the user to set this app as a default home screen and setting it as such */ public void lock() { //todo } /** restores the users old home screen */ public void unlock() { //todo } } } Any changes can be discussed to fit the actual implementation.