Saving and restoring the Activity state

In this section, you’ll explore how your Activity saves and restores the state. As you learned in Exercise 2.01 – logging the Activity callbacks, configuration changes, such as rotating the phone, cause the Activity to be recreated.In these scenarios, it is important to preserve the state of the Activity and then restore it. In the next two exercises, you’ll work through an example, ensuring that data is restored using a long-established technique to save and restore Activity state.

Exercise 2.02 – saving and restoring state

In this exercise you are going to create a simple app that generates a random number:

1. Create an application called Save and Restore with an empty Activity.
2. Open up the strings.xml file (located in app | res | values | strings.xml in the Android view of the Project Window or at app | src | main | res | values | strings.xml in the...