What Activity's lifecycle callbacks are executed when Android orientation is changed?

Question

I got stuck while debugging a situation which involved orientation change and some null returns.

My question is divided into :

1) What callbacks of Activity's lifecycle are executed when orientation is changed.

2) What callbacks of Fragment's lifecycle are executed when orientation is changed.

3) If we merge point 2 and 3 (which is usually the case with fragments overlying an Activity), what will be the callback execution flow in terms of an Activity having a Fragment(flow of execution?).

EDIT

Shedding some light on the question, if no configChanges are defined in android manifest file i.e. :

If any configuration change occurs that is not selected to be reported by that attribute, then instead of reporting it the system will stop and restart the activity (to have it launched with the new configuration).

What Lifecycle callbacks of activity and fragment will be executed?

Answer 1

First of all, in AndroidManifest add it to your activity: android:configChanges="orientation"

1). onConfigurationChanged
2). Nothing, but you can implement your method and call it from activity's onConfigurationChanged
3). The flow will be Activity.onConfigurationChanged -> Fragment.yourMethod

Hope this helps.

UPDATED

Here is your flow when your start activity first time:

Activity.onCreate
Activity.onStart
Fragment.onAttach
Fragment.onCreate
Fragment.onCreateView
Fragment.onViewStateRestored
Fragment.onStart
Activity.onResume
Fragment.onResume

Here is flow after orientation changed:

Activity.onPause
Fragment.onPause
Activity.onSaveInstanceState
Fragment.onSaveInstanceState
Activity.onStop
Fragment.onStop
Activity.onDestroy
Fragment.onDestroy
Fragment.onDetach
Fragment.onAttach
Fragment.onCreate
Activity.onCreate
Activity.onStart
Fragment.onCreateView
Fragment.onViewStateRestored
Fragment.onStart
Activity.onRestoreInstanceState
Activity.onResume
Fragment.onResume

Here is code to check it:

public class FooActivity extends FragmentActivity {

    private static final String LOG_TAG = FooActivity.class.getSimpleName() + "_TAG";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.i(LOG_TAG, "Activity.onCreate");
        setContentView(R.layout.activity_foo);
        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.container, new BarFragment())
                    .commit();
        }
    }


    @Override
    protected void onPause() {
        Log.i(LOG_TAG, "Activity.onPause");
        super.onPause();
    }

    @Override
    protected void onStop() {
        Log.i(LOG_TAG, "Activity.onStop");
        super.onStop();
    }

    @Override
    protected void onDestroy() {
        Log.i(LOG_TAG, "Activity.onDestroy");
        super.onDestroy();
    }

    @Override
    protected void onResume() {
        Log.i(LOG_TAG, "Activity.onResume");
        super.onResume();
    }

    @Override
    protected void onStart() {
        Log.i(LOG_TAG, "Activity.onStart");
        super.onStart();
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        Log.i(LOG_TAG, "Activity.onConfigurationChanged");
        super.onConfigurationChanged(newConfig);
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        Log.i(LOG_TAG, "Activity.onSaveInstanceState");
        super.onSaveInstanceState(outState);
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        Log.i(LOG_TAG, "Activity.onRestoreInstanceState");
        super.onRestoreInstanceState(savedInstanceState);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class BarFragment extends Fragment {

        public BarFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            Log.i(LOG_TAG, "Fragment.onCreateView");
            View rootView = inflater.inflate(R.layout.fragment_bar, container, false);
            return rootView;
        }

        @Override
        public void onCreate(Bundle savedInstanceState) {
            Log.i(LOG_TAG, "Fragment.onCreate");
            super.onCreate(savedInstanceState);
        }

        @Override
        public void onAttach(Activity activity) {
            Log.i(LOG_TAG, "Fragment.onAttach");
            super.onAttach(activity);
        }

        @Override
        public void onViewStateRestored(Bundle savedInstanceState) {
            Log.i(LOG_TAG, "Fragment.onViewStateRestored");
            super.onViewStateRestored(savedInstanceState);
        }

        @Override
        public void onSaveInstanceState(Bundle outState) {
            Log.i(LOG_TAG, "Fragment.onSaveInstanceState");
            super.onSaveInstanceState(outState);
        }

        @Override
        public void onResume() {
            Log.i(LOG_TAG, "Fragment.onResume");
            super.onResume();
        }

        @Override
        public void onStart() {
            Log.i(LOG_TAG, "Fragment.onStart");
            super.onStart();
        }

        @Override
        public void onConfigurationChanged(Configuration newConfig) {
            Log.i(LOG_TAG, "Fragment.onConfigurationChanged");
            super.onConfigurationChanged(newConfig);
        }

        @Override
        public void onPause() {
            Log.i(LOG_TAG, "Fragment.onPause");
            super.onPause();
        }

        @Override
        public void onStop() {
            Log.i(LOG_TAG, "Fragment.onStop");
            super.onStop();
        }

        @Override
        public void onDetach() {
            Log.i(LOG_TAG, "Fragment.onDetach");
            super.onDetach();
        }

        @Override
        public void onDestroy() {
            Log.i(LOG_TAG, "Fragment.onDestroy");
            super.onDestroy();
        }
    }
}

Answer 2

onConfigurationChanged() method

@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
// Checks the orientation of the screen
if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE) {
    Toast.makeText(this, "landscape", Toast.LENGTH_SHORT).show();
} else if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT){
    Toast.makeText(this, "portrait", Toast.LENGTH_SHORT).show();
 }  }

add this code in your AndroidManifest.xml

<activity android:name=".MyActivity"
      android:configChanges="orientation|keyboardHidden"
      android:label="@string/app_name">

You can also check these Activity and Fragment