Error on android 4.2, button back -

I have a problem with my app, but only with Android 4.2. I explain the methodology: - The first activity is entering entry and password and allowing connections - when I am connected I will start the main menu of the application. If you use the back button, you do not come back into the login activity with the system. Exact (0) that comes to the home screen of your smartphone.

However, it works on all versions 4.2 but with Android 4.2 this app is killing and restarting the login activity.

Do you have an idea?

class increases your activity activity tools OnClickListener {... @ Override Public Zero OnClick (See V) {switch (v.getId ()) {case android.r.id.home: // Do your thing here .. Break; Case android RID. Back: // or here, if you like brakes; }}}