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My MainActivity is loading a fragment (there are 3 in total, controlled by a BottomNavigationBar). Each fragment receive data from LocalBroadcastManager, which is sent from an AsyncTask (since it need to do some network tasks), which is initialized from NotificationListenerService (it gets some music information).

Initially I loaded all the views directly into MainActivity, and they worked well, but since they are three different types of information, I decided to separate them into fragments. Now, only the fragment that is being showed get the data. If I switch to another fragment, it doesn't show anything until NotificationListenerService initialize the tasks again (it only happens when music state is changed). And if I return to the fragment that was showing the data, now it doesn't show it too.

Here is the code from one of my fragments (the three ones follow the same estructure):

String lastFmResults;

String lastFmKodes;

String lastFmDescriptions;



LinearLayout lastFmCards;



@Nullable

@Override

public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

    View view = inflater.inflate(R.layout.fragment_last_fm, container, false);



    lastFmCards = (LinearLayout) view.findViewById(R.id.last_fm_cards);



    LocalBroadcastManager.getInstance(getContext()).registerReceiver(broadcastReceiverLastFm, new IntentFilter("LastFM"));



    return view;

}



private BroadcastReceiver broadcastReceiverLastFm = new BroadcastReceiver() {

    @Override

    public void onReceive(Context context, Intent intent) {

        Bundle extras = intent.getExtras();

        lastFmResults = extras.getStringArray("values");

        lastFmKodes = extras.getStringArray("names");

        lastFmDescriptions = extras.getStringArray("descriptions");



        updateLastFmCards();

    }

};

And here is my MainActivity:

ColorsFragment colorsFragment;

LyricsFragment lyricsFragment;

LastFmFragment lastFmFragment;



BottomNavigationView bottomNavigationView;



@Override

protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);



    if (!isNotificationServiceRunning()) {

        startActivity(new Intent("android.settings.ACTION_NOTIFICATION_LISTENER_SETTINGS"));

    }



    colorsFragment = new ColorsFragment();

    lyricsFragment = new LyricsFragment();

    lastFmFragment = new LastFmFragment();



    bottomNavigationView = (BottomNavigationView) findViewById(R.id.bottom_navigation);

    bottomNavigationView.setOnNavigationItemSelectedListener(menuItem -> {

        Fragment fragment = null;



        switch (menuItem.getItemId()) {

            case R.id.nav_colors:

                fragment = colorsFragment;

                break;

            case R.id.nav_lyrics:

                fragment = lyricsFragment;

                break;

            case R.id.nav_last_fm:

                fragment = lastFmFragment;

                break;

        }



        getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, fragment).commit();



        return true;

    });



    getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, colorsFragment).commit();

}

I expect the fragments will load the data sent to them even though they are not yet being displayed in MainActivity.

I solved it following this guide:
https://medium.com/@oluwabukunmi.aluko/bottom-navigation-view-with-fragments-a074bfd08711

Instead of replace(), it says I have to use show() and hide(). I only had to modify my MainActivity:

final ColorsFragment colorsFragment = new ColorsFragment();

final LyricsFragment lyricsFragment = new LyricsFragment();

final LastFmFragment lastFmFragment = new LastFmFragment();



final FragmentManager fragmentManager = getSupportFragmentManager();

Fragment activeFragment = colorsFragment;



BottomNavigationView bottomNavigationView;



@Override

protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);



    if (!isNotificationServiceRunning()) {

        startActivity(new Intent("android.settings.ACTION_NOTIFICATION_LISTENER_SETTINGS"));

    }



    bottomNavigationView = (BottomNavigationView) findViewById(R.id.bottom_navigation);

    bottomNavigationView.setOnNavigationItemSelectedListener(menuItem -> {



        switch (menuItem.getItemId()) {

            case R.id.nav_colors:

                fragmentManager.beginTransaction().hide(activeFragment).show(colorsFragment).commit();

                activeFragment = colorsFragment;

                break;

            case R.id.nav_lyrics:

                fragmentManager.beginTransaction().hide(activeFragment).show(lyricsFragment).commit();

                activeFragment = lyricsFragment;

                break;

            case R.id.nav_last_fm:

                fragmentManager.beginTransaction().hide(activeFragment).show(lastFmFragment).commit();

                activeFragment = lastFmFragment;

                break;

        }



        return true;

    });



    fragmentManager.beginTransaction().add(R.id.fragment_container, lastFmFragment, "2").hide(lastFmFragment).commit();

    fragmentManager.beginTransaction().add(R.id.fragment_container, lyricsFragment, "1").hide(lyricsFragment).commit();

    fragmentManager.beginTransaction().add(R.id.fragment_container, colorsFragment, "0").commit();

}