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

Question

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

Answer 1

String activityState;
@Override 
public void onCreate(Bundle savedInstanceState) {
// call the super class onCreate to complete the creation of activity like 
// the view hierarchy 
super.onCreate(savedInstanceState);

// recovering the instance state 
if (savedInstanceState != null) {
     activityState = savedInstanceState.getString(STATE_KEY);
 } 

   setContentView(R.layout.main_activity);
   mTextView = (TextView) findViewById(R.id.text_view);
} 

//This callback is called only when there is a saved instance previously saved using //onSaveInstanceState(). We restore some state in onCreate() while we can optionally restore // other state here, possibly usable after onStart() has completed. // The savedInstanceState Bundle is same as the one used in onCreate().

@Override 
public void onRestoreInstanceState(Bundle savedInstanceState) {
 mTextView.setText(savedInstanceState.getString(STATE_KEY));
  } 


// invoked when the activity may be temporarily destroyed, save the instance 
//state here 
//this method will be called before onstop

@Override 
 public void onSaveInstanceState(Bundle outState) {
    outState.putString(STATE_KEY, activityState);

    // call superclass to save any view hierarchy 
    super.onSaveInstanceState(outState);
}