The activity lifecycle is central to Android development. Although it is quite well defined, it does take a bit of getting used to. One aspect new developers perhaps struggle with is that rotating the device will by default destroy and recreate the activity.
A well behaved activity will restore its state after a rotation so the user can continue using the application with no lose of state. e.g. EditText widgets should restore the text they contained when the device was rotated and a long running operation should resume without restarting. Continue reading