在Android中创建登录屏幕/活动的正确方式是什么?

I am working on an Android application that requires a user to login before doing anything else. Currently I have created main Activity named LoginScreen and upon successful login this activity launches another Activity called Home. But I see a problem with this approach. What if user presses back button from Home activity? I dont want user going back to login screen. what is the correct way of stopping the user from doing that. Do I need to handle Key Press events?I am working on an Android application that req