Android™ How to Program, Second Edition

onCreate’s Bundle Parameter

During the app’s execution, the user could change the device’s configuration by rotating the device or sliding out a hard keyboard. For a good experience, the app should continue operating smoothly through such configuration changes. When the system calls onCreate, it passes a Bundle argument containing the Activity’s saved state, if any. Typically, you save state in Activity methods onPause or onSaveInstanceState (demonstrated in later apps). Line 38 calls the superclass’s onCreate method, which is required when overriding onCreate.