Data is not updated for two Pages in Parallel Android

Question

In my app I have two pages, one page shows the paerson information and another page shows the news information. I am using Realm database for local storage. I have used some mock data of persons and news, which will appear at the starting of the app. Now the problem is when I run my app, at first I click on person button and it is showing the person information, but if I click News button it is completely blank. nothing is shown on the window. Alterntively after uninstalling the app if I click news button at first, the news information is showing, but after clicking the person button, the person page is completely blank. The problem both pages are not updated simultaneously. I do not what would be the problem in this case.

I am giving my code in short

PersonPage Activity is

public class PersonPage extends AppCompatActivity implements PersonAdapter.PersonListListener{

private RecyclerView recyclerView;
private PersonAdapter adapter;
private Realm personRealm;
private RealmResults<PersonModel> personResult;

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

    personRealm = Realm.getDefaultInstance();
    recyclerView = (RecyclerView) findViewById(R.id.person_recycler);

    setUpRecycler();

    if (!Prefs.with(this).getPreLoad()) {
        setRealmData();
    }
    showAllPersons();

}

private void showAllPersons() {
    personResult = personRealm.where(PersonModel.class).findAll();
    setAdapter(personResult);
    adapter.notifyDataSetChanged();
}

private void setAdapter(RealmResults<PersonModel> results) {

    adapter = new PersonAdapter(this, personRealm.where(PersonModel.class).findAllSortedAsync("id"),this);
    recyclerView.setAdapter(adapter);
    adapter.notifyDataSetChanged();
}
private void setUpRecycler() {

    recyclerView.setHasFixedSize(true);
    final LinearLayoutManager layoutManager = new LinearLayoutManager(this);
    layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
    recyclerView.setLayoutManager(layoutManager);
}

private void setRealmData(){

    List<PersonModel> colleague = new ArrayList<>();
    PersonModel model = new PersonModel();
    model.setId(1+System.currentTimeMillis());
    model.setName("Name1");
    model.setCompany("Comapny1");
    model.setTitle("Title1");
    person.add(model);
    model = new PersonModel();
    model.setId(2+System.currentTimeMillis());
    model.setName("Name2");
    model.setCompany("Comapny2");
    model.setTitle("Title1");
    person.add(model);

    for (PersonModel realmModel : person) {
            // Persist the colleague data
        colleagueRealm.beginTransaction();
        colleagueRealm.copyToRealm(realmModel);
        colleagueRealm.commitTransaction();
    }

    Prefs.with(this).setPreLoad(true);
}

@Override
protected void onDestroy() {
    if (personRealm!= null)
        personRealm.close();
    super.onDestroy();
   }
}

My NewsPage Activity is

  public class NewsPage extends AppCompatActivity implements NewsAdapter.NewsChangeListener {

    private RecyclerView recyclerView;
    private NewsAdapter adapter;
    private Realm newsRealm;
    private RealmResults<NewsModel> newsResult;


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

        newsRealm = Realm.getDefaultInstance();
        recyclerView = (RecyclerView) findViewById(R.id.news_recycler);

        setUpRecycler();

        if (!Prefs.with(this).getPreLoad()) {
            setRealmData();
        }
        showAllNews();


    }
    private void showAllNews() {
        newsResult = newsRealm.where(NewsModel.class).findAll();
        setAdapter(newsResult);
        adapter.notifyDataSetChanged();
    }

    private void setAdapter(RealmResults<NewsModel> results) {
        adapter = new NewsAdapter(this, newsRealm.where(NewsModel.class).findAllSortedAsync("id"),this);
        recyclerView.setAdapter(adapter);
        adapter.notifyDataSetChanged();
    }

    private void setUpRecycler() {

        recyclerView.setHasFixedSize(true);   
        final LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
        recyclerView.setLayoutManager(layoutManager);
    }

    private void setRealmData() {

        List<NewsModel> newsItem = new ArrayList<>();

        NewsModel model = new NewsModel();
        model.setId(1+System.currentTimeMillis());
        model.setImage(R.drawable.image1);
        model.setTitle("Title1");
        model.setDate("01.02.2017");
        model.setDetail("Deatils1");
        newsItem.add(model);

        model = new NewsModel();
        model.setId(2+System.currentTimeMillis());
        model.setImage(R.drawable.image2);
        model.setTitle("Title2");
        model.setDate("24.05.2017");
        model.setDetail("Deatils2");
        newsItem.add(model);


        for (NewsModel realmModel : newsItem) {
            // Persist the news data
            newsRealm.beginTransaction();
            newsRealm.insertOrUpdate(realmModel);
            newsRealm.commitTransaction();
        }

        Prefs.with(this).setPreLoad(true);
    }


    @Override
    protected void onDestroy() {
        if (newsRealm!= null)
            newsRealm.close();
        super.onDestroy();
     }
   }

Answer 1

The problem here seems to be this statement.

if (!Prefs.with(this).getPreLoad()) {
        setRealmData();
    }

Every time you load your Persons list you are setting getPreLoad to true;

Prefs.with(this).setPreLoad(true);

When you load the News list it wont load the model from database because it will always get this statement Prefs.with(this).getPreLoad() as false.

EDIT:

you can use different identifiers for Person and News. In your Prefs class create a seperate identifier for both and set them in their respective classes:

In your Prefs class add these methods:

public static void setPreLoadPerson(boolean shouldLoad) {

    sharedPreferences.edit().putBoolean("loadperson", shouldLoad);
}

public static void setPreLoadNews(boolean shouldLoad) {

    sharedPreferences.edit().putBoolean("loadNews", shouldLoad);
}

public static boolean getPreLoadPerson() {
    return sharedPreferences.getBoolean("loadperson", false);
}
public static boolean getPreLoadNews() {
    return sharedPreferences.getBoolean("loadNews", false);
}

Then in your respective classes get and set it according to you need.

PS : i wrote this code without any compiler so you might get some typo.