Android - Double lifecycle sequence from landscape to portrait

问题

I'm monitoring an Activity lifecycle to learn more on it, so I put a Log.d() call in almost every method of the cycle.

I'm watching particularly the sequence:

[A]onSaveInstanceState() - onPause() - onStop() - onDestroy() - onStart() - [B]onRestoreInstanceState()

See Activity Lifecycle

Switching a 2.2 Froyo emulator with Ctrl-F11 from portrait to landscape I can see one round from [A] to [B].

What is strange to me is that switching back from landscape to portrait I can see two round from [A] to [B].

onSaveInstanceState() - onPause() - onStop() - onDestroy() - onStart() - onRestoreInstanceState()
onSaveInstanceState() - onPause() - onStop() - onDestroy() - onStart() - onRestoreInstanceState()

This is creating me lots of issues in saving/restoring the activity state.

How can it be? Why is it so?

Edited: Using a 2.3.3 Gingerbread emulator the sequence runs only once. But 2.3.3 emulator has a known bug that prevents it from rotating correctly!

回答1:

Rotation in emulator is different from Accelerator rotation. It actually simulates an open-keyboard. These are two different events, which cause two different lify-cycle flows.

回答2:

Its happen some times on emulators, check it on real device, it works properly on real devices.

来源：https://stackoverflow.com/questions/5484108/android-double-lifecycle-sequence-from-landscape-to-portrait