Android Fragments: Maintaining State After Configuration Change

FeedFragment.java

//
//
// Changes made to in FeedFragment.java
//
//	

//
// Added private member to store position
//
private int position;

//
// Added setRetainInstance(true); to onCreate()
//
@Override
public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);

	Log.i(TAG, "Entered FeedFragment.onCreate()");

	setPosition(-1);

  // retain this fragment
  setRetainInstance(true);
}

//
// Added getter & setter for position member
//
public int getPosition()
{
	return position;
}

public void setPosition(int position)
{
	this.position = position;
}

//
// Call setPosition() when updateFeedDisplay() is called
//
void updateFeedDisplay(int position) {

	Log.i(TAG, "Entered FeedFragment.updateFeedDisplay()");
			
	mTextView = (TextView) getView().findViewById(R.id.feed_view);
	mTextView.setText(feedFragmentData.getFeed(position));

	setPosition(position);

}

FriendsFragment.java

//
//
// Changes made to in FriendsFragment.java
//
//	

//
// Add setRetainInstance(true); to onCreate() method in FriendsFragment.java
//
@Override
public void onCreate(Bundle savedInstanceState) {
	super.onCreate(savedInstanceState);

	Log.i(TAG, "Entered FriendsFragment.onCreate()");

	// use different layout definition, depending on whether device is pre-
	// or post-honeycomb

	int layout = Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB ? android.R.layout.simple_list_item_activated_1
			: android.R.layout.simple_list_item_1;

	// Set the list adapter for this ListFragment
	setListAdapter(new ArrayAdapter<String>(getActivity(), layout, FRIENDS));
      
  // retain this fragment
	setRetainInstance(true);
}

MainActivity.java

//
//
// Changes made in MainActivity.java
//
//

//
// Check to see if mFeedFragment or mFriendsFragment already exist
// in the FragmentManager before instantiating new FriendsFragment
// (to avoid redundant instantiation)
//
@Override
protected void onCreate(Bundle savedInstanceState) {
	super.onCreate(savedInstanceState);
	setContentView(R.layout.main_activity);

	Log.i(TAG, "Entered MainActivity.onCreate()");
	

	// If the layout is single-pane, create the FriendsFragment 
	// and add it to the Activity

	if (!isInTwoPaneMode()) {
		
		// find the retained friends fragment on activity restarts
    FragmentManager fm = getFragmentManager();
    if(fm.getBackStackEntryCount() == 0)
      mFriendsFragment = (FriendsFragment) fm.findFragmentById(R.id.fragment_container);
    else
      mFeedFragment = (FeedFragment) fm.findFragmentById(R.id.fragment_container);
		
		if(mFriendsFragment == null && mFeedFragment == null)
		{
			mFriendsFragment = new FriendsFragment();

			//TODO 1 - add the FriendsFragment to the fragment_container
			FragmentTransaction ft = getFragmentManager().beginTransaction();
			ft.add(R.id.fragment_container, mFriendsFragment);
			ft.commit();
		}
		
	} else {
		
		// Otherwise, save a reference to the FeedFragment for later use
		 mFeedFragment = (FeedFragment) getFragmentManager()
				.findFragmentById(R.id.feed_frag);
	}

}