Called to retrieve per-instance state from an activity before being killed so that the state can be restored in
Bundle populated by this method will be passed to both).
This method is called before an activity may be killed so that when it comes back some time in the future it can restore its state. For example, if activity B is launched in front of activity A, and at some point activity A is killed to reclaim resources, activity A will have a chance to save the current state of its user interface via this method so that when the user returns to activity A, the state of the user interface can be restored via
Do not confuse this method with activity lifecycle callbacks such as
onPause(), which is always called when an activity is being placed in the background or on its way to destruction, or
onStop() which is called before destruction. One example of when
onStop() is called and not this method is when a user navigates back from activity B to activity A: there is no need to call
onSaveInstanceState(Bundle) on B because that particular instance will never be restored, so the system avoids calling it. An example when
onPause() is called and not
onSaveInstanceState(Bundle) is when activity B is launched in front of activity A: the system may avoid calling
onSaveInstanceState(Bundle) on activity A if it isn't killed during the lifetime of B since the state of the user interface of A will stay intact.
The default implementation takes care of most of the UI per-instance state for you by calling
onSaveInstanceState() on each view in the hierarchy that has an id, and by saving the id of the currently focused view (all of which is restored by the default implementation of
onRestoreInstanceState(Bundle)). If you override this method to save additional information not captured by each individual view, you will likely want to call through to the default implementation, otherwise be prepared to save all of the state of each view yourself.
|outState||Bundle in which to place your saved state.|
This method is called after
onStart() when the activity is being re-initialized from a previously saved state, given here in savedInstanceState. Most implementations will simply use
onCreate(Bundle) to restore their state, but it is sometimes convenient to do it here after all of the initialization has been done or to allow subclasses to decide whether to use your default implementation. The default implementation of this method performs a restore of any view state that had previously been frozen by
|savedInstanceState||the data most recently supplied in |