committedandroider committedandroider - 5 months ago 16
Android Question

Are fragments saved by default with savedInstanceState?

I read on What's onCreate(Bundle savedInstanceState)
that onsaveinstancestate gives you a bundle of the previous state of the application(if the orientation of the screen changed.

I looked on the Android docs(http://developer.android.com/training/basics/activity-lifecycle/recreating.html) and saw that you have to manually put the values you want saved as key value pairs. Their code for doing so was

static final String STATE_SCORE = "playerScore";
static final String STATE_LEVEL = "playerLevel";
...

@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
// Save the user's current game state
savedInstanceState.putInt(STATE_SCORE, mCurrentScore);
savedInstanceState.putInt(STATE_LEVEL, mCurrentLevel);


My question is for fragments, are they automatically reattached when the orientation changes and the activity recreated? Would you have to put code to save it into a bundle?
Heres facebook code for this situation that I am trying to understand

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

if (savedInstanceState == null) {
// Add the fragment on initial activity setup
mainFragment = new MainFragment();
getSupportFragmentManager()
.beginTransaction()
.add(android.R.id.content, mainFragment)
.commit();
} else {
// Or set the fragment from restored state info
mainFragment = (MainFragment) getSupportFragmentManager()
.findFragmentById(android.R.id.content);
}


}

Answer

To keep a fragment when an Activity gets destroyed, so it automatically reataches, you should call

Fragment.setRetainInstance(true)

in the Fragment's constructor. Nothing is saved by default in onSaveInstanceState()