My fragments keep recreating whenever I reclick or navigate to the next fragment

Question

I have implemented the new architecture component on my android app, but unfortunately handling the states of these fragments has become a nightmare for me. Whenever I press the icon of the fragment, the fragment is recreated every time I navigate. How can I handle this or rather save these fragments states?

Here is my main activity handling the five fragments:

public class MainActivityCenterofInformation extends AppCompatActivity {

    BottomNavigationView bottomNavigationView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate (savedInstanceState);
        setContentView (R.layout.activity_maincict);

        setUpNavigation ();
    }

    public  void setUpNavigation(){
        bottomNavigationView = findViewById (R.id.bottom_nav_cict);
        NavHostFragment navHostFragment = (NavHostFragment)getSupportFragmentManager ()
                .findFragmentById (R.id.nav_host_fragment_cict);
        NavigationUI.setupWithNavController (bottomNavigationView, navHostFragment.getNavController ());
    }

    //adding animations to the fragment
}

I can't read Kotlin so please direct me to Java, thanks.

Answer 1

I am not entirely sure if this is the answer you are looking for but if you are concerned about managing state the modern way of managing state is by using something called a view model. View models are a component of the MVVM architecture. Their purpose is to hold and expose data to your fragment/activity to display. With the navigation architecture, if you store the data related to each fragment in this view model appropriately your state will be retained in the view model.

That being said I would personally suggest looking into MVVM architecture as well as view models specifically. Otherwise, a brute force for retaining state is by using the savedInstance state throughout fragments and manually saving and recovering important data.

Links: - Android View Model Component - Android architecture guide

Answer 2

I think you might need to prevent recreating the fragment upon clicking bottom nav view item twice. bottomNavigationView.setOnNavigationItemReselectedListener { /*Nothing to ignore reselection*/} after NavigationUI.setupWithNavController (bottomNavigationView, navHostFragment.getNavController ());