Learning Android™ Application Programming: A Hands-On Guide to Building Android Applications

Understanding the Activity Lifecycle

As users continually navigate through the screens of your application, activities switch between different states in their lifecycle. When an activity is called for the first time, the Android system calls a series of methods that start up the user interface. Using these methods, you can create the look and feel of your activity as well as create other components.

If the user starts another activity or even switches to another app, Android calls another series of methods as your activity moves into the background. For example, if the user moves to a different app, you might terminate all data connections that your app is currently using. But be careful. When this happens, your application state may be lost, ...