Fool-proof way to handle Fragment on orientation change

You are creating a new fragment every time you turn the screen in your activity onCreate(); But you are also maintaining the old ones with super.onCreate(savedInstanceState);. So maybe set tag and find the fragment if it exist, or pass null bundle to super.

This took me a while to learn and it can really be a bi**** when you are working with stuff like viewpager.

I'd recommend you to read about fragments an extra time as this exact topic is covered.

Here is an example of how to handle fragments on a regular orientation change:

Activity:

public class MainActivity extends FragmentActivity {    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        if (savedInstanceState == null) {            TestFragment test = new TestFragment();            test.setArguments(getIntent().getExtras());            getSupportFragmentManager().beginTransaction().replace(android.R.id.content, test, "your_fragment_tag").commit();        } else {            TestFragment test = (TestFragment) getSupportFragmentManager().findFragmentByTag("your_fragment_tag");        }    }}

Fragment:

public class TestFragment extends Fragment {    public static final String KEY_ITEM = "unique_key";    public static final String KEY_INDEX = "index_key";    private String mTime;    @Override    public View onCreateView(LayoutInflater inflater, ViewGroup container,            Bundle savedInstanceState) {        View view = inflater.inflate(R.layout.fragment_layout, container, false);        if (savedInstanceState != null) {            // Restore last state            mTime = savedInstanceState.getString("time_key");        } else {            mTime = "" + Calendar.getInstance().getTimeInMillis();        }        TextView title = (TextView) view.findViewById(R.id.fragment_test);        title.setText(mTime);        return view;    }    @Override    public void onSaveInstanceState(Bundle outState) {        super.onSaveInstanceState(outState);        outState.putString("time_key", mTime);    }}

A good guideline about how to retain data between orientation changes and activity recreation can be found in android guidelines.

Summary:

1. make your fragment retainable:

   setRetainInstance(true);

2. Create a new fragment only if necessary (or at least take data from it)

   dataFragment = (DataFragment) fm.findFragmentByTag("data");// create the fragment and data the first timeif (dataFragment == null) {