When exactly are onSaveInstanceState() and onRestoreInstanceState() called?

Question

The following figure (from the official doc) describes the well-known lifecycle of an Android activity:

On the other hand, when the activity is destroyed by the system (for example because memory needs to be reclaimed), the state of the activity is sometimes automatically saved and restored by means of the methods onSaveInstanceState() and onRestoreInstanceState(), as illustrated by the following figure (also from the official doc):

I'm aware that onSaveInstanceState() is not always called when an activity is about to be destroyed. For example, if it is destroyed because the user has pressed the "back" button, the activity state is not preserved. But in the cases when the state is saved and restored, and onSaveInstanceState() / onRestoreInstanceState() get called, when exactly are they called?

For example, according to the above figures, onRestoreInstanceState() might be called before onStart(), or after onStart() but before onResume(), or after onResume(). Similarly, several possibilities exist for onSaveInstanceState(). So when are they called exactly?

Ideally, what I would like is to see a combined diagram showing the activity lifecycle states and the save/restore methods, if that exists.

Answer 1

Per the documentation:

void onRestoreInstanceState (Bundle savedInstanceState)

This method is called between onStart() and onPostCreate(Bundle).

void onSaveInstanceState (Bundle outState)

If called, this method will occur after onStop() for applications targeting platforms starting with Build.VERSION_CODES.P. For applications targeting earlier platform versions this method will occur before onStop() and there are no guarantees about whether it will occur before or after onPause().

Answer 2

As per doc1 and doc2

onSaveInstanceState

Prior to Honeycomb, activities were not considered killable until after they had been paused, meaning that onSaveInstanceState() was called immediately before onPause(). Beginning with Honeycomb, however, Activities are considered to be killable only after they have been stopped, meaning that onSaveInstanceState() will now be called before onStop() instead of immediately before onPause().

onRestoreInstanceState

This method is called between onStart() and onPostCreate(Bundle) when the activity is being re-initialized from a previously saved state