How to Show Preload data to RecyclerView using Realm

Question

In my App I am using Realm as local database. I am using recyclerview widget to show these data. Now initiallay I want to show some preload data in recycler view which would be stored in realm as well. then I will implement add, edit, delete method. But I am having fatal error while trying to run this app. I am very new in Realm. I cannot identify which problem is this.

I have Solved this problem with the help of answer code. here is the solution for this.

Solved Code

And My Activity Class is

public class MyColleaguesPage extends AppCompatActivity {

private RecyclerView recyclerView;
private MyColleaguesAdapter adapter;
private Realm colleagueRealm;
private List<MyColleagueModel> colleagueObject;
private RealmResults<MyColleagueModel> dataResult;
private static final String DIALOG_TAG = "EmployeeDialog";

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

    colleagueRealm = Realm.getDefaultInstance();
    recyclerView = (RecyclerView) findViewById(R.id.colleagues_recycler);

    setUpRecycler();

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

 }

private void showAllPersons() {
    dataResult = colleagueRealm.where(MyColleagueModel.class).findAll();
    setAdapter(dataResult);
    adapter.notifyDataSetChanged();
 }
//find all objects in the Book.class
private void setAdapter(RealmResults<MyColleagueModel> results) {
    adapter = new MyColleaguesAdapter(this, results);
    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<MyColleagueModel> colleague = new ArrayList<>();
    MyColleagueModel model = new MyColleagueModel();
    model.setId(1 + System.currentTimeMillis());
    model.setName("Name1");
    model.setCompany("Comapny1");
    model.setTitle("Title1");
    colleague.add(model);

    model = new MyColleagueModel();
    model.setId(2 + System.currentTimeMillis());
    model.setName("Name2");
    model.setCompany("Comapny2");
    model.setTitle("Title1");
    colleague.add(model);

    model = new MyColleagueModel();
    model.setId(3 + System.currentTimeMillis());
    model.setName("Name3");
    model.setCompany("Comapny3");
    model.setTitle("Title3");
    colleague.add(model);


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

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

 }

.....

What version of Realm are you using? – EpicPandaForce Aug 04 '17 at 14:45 — EpicPandaForce, Aug 04 '17 at 14:45

EpicPandaForce · Accepted Answer · 2017-08-08T10:30:41.017

To fix immediate problem

private void setRealmData(){
    List<MyColleagueModel> colleague = new ArrayList<>();

    MyColleagueModel model = new MyColleagueModel();
    model.setId(1 + System.currentTimeMillis());
    model.setName("Name1");
    model.setCompany("Comapny1");
    model.setTitle("Title1");
    colleague.add(model);

    model.setId(2 + System.currentTimeMillis());
    model.setName("Name2");
    model.setCompany("Comapny2");
    model.setTitle("Title1");
    colleague.add(model);

    model.setId(3 + System.currentTimeMillis());
    model.setName("Name3");
    model.setCompany("Comapny3");
    model.setTitle("Title3");
    colleague.add(model);

should be

private void setRealmData(){
    List<MyColleagueModel> colleague = new ArrayList<>();

    MyColleagueModel model = new MyColleagueModel();
    model.setId(1 + System.currentTimeMillis());
    model.setName("Name1");
    model.setCompany("Comapny1");
    model.setTitle("Title1");
    colleague.add(model);

    model = new MyColleagueModel();
    model.setId(2 + System.currentTimeMillis());
    model.setName("Name2");
    model.setCompany("Comapny2");
    model.setTitle("Title1");
    colleague.add(model);

    model = new MyColleagueModel();
    model.setId(3 + System.currentTimeMillis());
    model.setName("Name3");
    model.setCompany("Comapny3");
    model.setTitle("Title3");
    colleague.add(model);

But based on Prefs.with(this).preload() you are basing your code on Ravi Tamada's tutorial which is full of terrible practices and I think it's still Realm 0.82.2.

Don't forget that latest version of Realm (at time of writing) is Realm 3.5.0, and you are better off with the official documentation.

For example, you should use RealmRecyclerViewAdapter provided by realm-android-adapters (official add-on) instead of using your own.

EDIT: Here is full solution

public class MyColleaguesPage extends AppCompatActivity implements ColleagueListListener {

    private Realm realm;
    private RecyclerView recyclerView;
    private MyColleaguesAdapter adapter;

    private static final String DIALOG_TAG = "EmployeeDialog";

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

        // Showing and Enabling clicks on the Home/Up button
        if (getSupportActionBar() != null) {
            getSupportActionBar().setDisplayHomeAsUpEnabled(true);
            getSupportActionBar().setDisplayShowHomeEnabled(true);
        }
        realm = Realm.getDefaultInstance();
        recyclerView = (RecyclerView) findViewById(R.id.colleagues_recycler);

        recyclerView.setHasFixedSize(true);
        final LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
        recyclerView.setLayoutManager(layoutManager);
        adapter = new MyColleaguesAdapter(this, realm.where(MyColleagueModel.class).findAllSortedAsync("id"));
        recyclerView.setAdapter(adapter);
     }

     @Override
     protected void onDestroy() {
        super.onDestroy();
        realm.close();
        realm = null;
     }
}        

public class InitialData implements Realm.Transaction {
    @Override
    public void execute(Realm realm) {
        List<MyColleagueModel> colleague = new ArrayList<>();
        MyColleagueModel model = new MyColleagueModel();
        model.setId(1 + System.currentTimeMillis());
        model.setName("Name1");
        model.setCompany("Comapny1");
        model.setTitle("Title1");
        colleague.add(model);

        model = new MyColleagueModel();
        model.setId(2 + System.currentTimeMillis());
        model.setName("Name2");
        model.setCompany("Comapny2");
        model.setTitle("Title1");
        colleague.add(model);

        model = new MyColleagueModel();
        model.setId(3 + System.currentTimeMillis());
        model.setName("Name3");
        model.setCompany("Comapny3");
        model.setTitle("Title3");
        colleague.add(model);


        for (MyColleagueModel realmModel : colleague) {
            realm.insertOrUpdate(realmModel);
        }
    }

    @Override
    public boolean equals(Object obj) {
        return obj != null && obj instanceof InitialData;
    }

    @Override
    public int hashCode() {
        return InitialData.class.hashCode();
    }
}

public class CustomApplication extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
        Realm.init(this);
        Realm.setDefaultConfiguration(new RealmConfiguration.Builder()
                      .deleteIfMigrationNeeded()
                      .initialData(new InitialData())
                      .build());
    }
}

<application name=".CustomApplication"
             .../>

public class MyColleaguesAdapter extends RealmRecyclerViewAdapter<MyColleagueModel, MyColleaguesAdapter.ColleagueHolder> {   
    public interface ColleagueListListener {
        void addPerson(MyColleagueModel colleagueModel);
        void editPerson(MyColleagueModel colleagueModel);
    }

    private final ColleagueListListener colleagueListListener;

    public MyColleaguesAdapter(ColleagueListListener colleagueListListener, RealmResults<MyColleagueModel> results) {
        super(results, true);
        this.colleagueListListener = colleagueListListener;
    }

    @Override
    public ColleagueHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        return new ColleagueHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.colleage_row_layout,parent,false));
    }

    @Override
    public void onBindViewHolder(ColleagueHolder holder, int position) {
        final MyColleagueModel myColleague = getData().get(position);
        holder.bind(myColleague);
    }

    public class ColleagueHolder extends RecyclerView.ViewHolder {

        public CardView cardView;
        public ImageView colleaguePicture;
        public TextView  colleagueName;
        public TextView  companyName;
        public TextView  jobTitle;

        public ColleagueHolder(View itemView) {
            super(itemView);
            //colleaguePicture=(ImageView)itemView.findViewById(R.drawable.profile_image);
            colleagueName=(TextView)itemView.findViewById(R.id.colleague_name);
            companyName=(TextView) itemView.findViewById(R.id.company_name);
            jobTitle=(TextView) itemView.findViewById(R.id.job_title);
            cardView=(CardView)itemView.findViewById(R.id.cardview_user);
          }
        }

        public void bind(MyColleagueModel myColleague) {
            holder.colleagueName.setText(myColleague.getName());
            holder.companyName.setText(myColleague.getCompany());
            holder.jobTitle.setText(myColleague.getTitle());
            holder.cardView.setTag(position);
            holder.cardView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    colleagueListListener.editPerson(myColleague);
                }
            });
        }
 }

Thank you for your code. Yes I write my code based on the example of Ravi Tamada's tutorial . I am still very new in android developing. Hence it was too much complicated for me to implement recyclerview with realm. I have read lots of article but nothing was explained in detail. I am still confusing to implement recyclerview with Realm. Particularly the adapter class. — , Aug 05 '17 at 08:25
You need to use RealmRecyclerViewAdapter from https://github.com/realm/realm-android-adapters and delete about half of the code you currently have (especially that `List` field you have, and replace it with `getData()` and `updateData()`) — EpicPandaForce, Aug 07 '17 at 07:37
I have updated my code. Could please have a look on my code. I used RecyclerView.Adapter. but this also work. the problem is with this code the data is not updated after adding a new information. if I click another optiop then it is updated. it would be reall nnice if you have look on my code — , Aug 07 '17 at 08:00
also could you please tell me how can I show preload data withour prefis class — , Aug 07 '17 at 08:01
Thank you very much for your code.I have create new issue. because in this issue, showing some preload data was the main question. and the answer of yours was solved this issue. if you do not mind could you plaese have a look on my new issue https://stackoverflow.com/questions/45542960/data-is-not-updated-promptly-after-adding-the-information-using-realm-in-android?noredirect=1#comment78045760_45542960 — , Aug 07 '17 at 09:05

Muthukrishnan Rajendran · Answer 2 · 2017-08-04T12:28:40.163

0

set unique value to model.setId(); in setRealmData() method, it will work,

You are trying set the primary key value which alreay exits.

private void setRealmData(){
        List<MyColleagueModel> colleague = new ArrayList<>();

        int id;
        try {
           id = 
colleagueRealm.where(MyColleagueModel.class).max("id").intValue() + 1;
        } catch(ArrayIndexOutOfBoundsException ex) {
           id = 0; // when there is no object in the database yet
        }
        MyColleagueModel model = new MyColleagueModel();
        model.setId(1 + id);
        model.setName("Name1");
        model.setCompany("Comapny1");
        model.setTitle("Title1");
        colleague.add(model);

        model.setId(2 + id);
        model.setName("Name2");
        model.setCompany("Comapny2");
        model.setTitle("Title1");
        colleague.add(model);

        model.setId(3 + id);
        model.setName("Name3");
        model.setCompany("Comapny3");
        model.setTitle("Title3");
        colleague.add(model);

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

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

Create auto increment in realm ref this SO answer

edited Aug 04 '17 at 12:28

answered Aug 04 '17 at 12:01

Muthukrishnan Rajendran

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Could you please explain a bit more. I am very new in developing area – Aug 04 '17 at 12:04
No in setRealmData() you are doing **model.setId(1 + System.currentTimeMillis());** search model.setId in that method you are doing in 3 places – Muthukrishnan Rajendran Aug 04 '17 at 12:19
you have in 3 place in that method – Muthukrishnan Rajendran Aug 04 '17 at 12:19
I have write some long number 123466. but still having the same error – Aug 04 '17 at 12:19
no don't do that, it should not be duplicate, that is the error, – Muthukrishnan Rajendran Aug 04 '17 at 12:21
Ok so How can I modify it. shall I do it 1, 2 or 3 – Aug 04 '17 at 12:22
what is max here .max("id").intValue() + 1; – Aug 04 '17 at 12:48
that is max value of you auto increment primary value – Muthukrishnan Rajendran Aug 04 '17 at 12:49
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/151065/discussion-between-muthukrishnan-rajendran-and-ktina). – Muthukrishnan Rajendran Aug 04 '17 at 12:55

How to Show Preload data to RecyclerView using Realm

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