How to handle two recyclerviews of the same layout in one activity?

Question

I am using an MVVM structure in my project. In one activity I have two recyclerviews and one adapter. They are both using the same tasks_layout. I set the data this way:

final UnsortedAdapter adapter = new UnsortedAdapter();
eatFrog.setHasFixedSize(true);
eatFrog.setLayoutManager(new LinearLayoutManager(this));
eatFrog.setAdapter(adapter);

biologicalRhythms.setAdapter(adapter);
biologicalRhythms.setLayoutManager(new LinearLayoutManager(this));
biologicalRhythms.setHasFixedSize(true);

viewModel.getUnsortedWhereDateIs(currentDate).observe(this, new Observer<List<Unsorted>>() {
            @Override
            public void onChanged(List<Unsorted> unsorted) {
                adapter.setData(EatAFrog(unsorted));
                eatAFrogList = EatAFrog(unsorted);

                adapter.setData(BiologicalRhythms(unsorted));
                biologicalList = BiologicalRhythms(unsorted);

            }
        });

The point is that each recyclerview gets data of the same class "Unsorted", but data went through two different algorithms. If I do it this way, then two recyclerviews will have the same data, that went through second algorithm.

I tried to do different things. Firstly, I tried to use another instance of my adapter to the second recyclerview, but in that case there was no data displayed in the first recyclerview:

 final UnsortedAdapter adapter = new UnsortedAdapter();
    eatFrog.setHasFixedSize(true);
    eatFrog.setLayoutManager(new LinearLayoutManager(this));
    eatFrog.setAdapter(adapter);
 final UnsortedAdapter adapter2 = new UnsortedAdapter();
    biologicalRhythms.setAdapter(adapter2);
    biologicalRhythms.setLayoutManager(new LinearLayoutManager(this));
    biologicalRhythms.setHasFixedSize(true);

Seconly, I tried to create another adapter class, the same as third. I also created another layout - tasks2_layout, where I only changed the ids of the elements. Then in second new adapter I also changed them in a viewholder class. My very first adapter looks like:

 List<Unsorted> list = new ArrayList<>();

@NonNull
@Override
public UnsortedViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    View itemView = LayoutInflater.from(parent.getContext())
            .inflate(R.layout.tasks_layout , parent, false);
    return new  UnsortedAdapter.UnsortedViewHolder(itemView);
}

@Override
public void onBindViewHolder(@NonNull UnsortedViewHolder holder, int position) {
    Unsorted data = list.get(position);
    holder.title.setText(data.getName());
    holder.date.setText(data.getDate());
    holder.category.setText(String.valueOf(data.getCategory()));
    holder.attach.setText(String.valueOf(data.isAttach()));
    holder.to.setText(String.valueOf(toTime(data.getDuration() + data.getTimeBegin())));
    holder.from.setText(String.valueOf(toTime(data.getTimeBegin())));
}

public void setData(List<Unsorted> unsortedList){
    this.list = unsortedList;
    notifyDataSetChanged();
}

@Override
public int getItemCount() {
    return list.size();
}

class UnsortedViewHolder extends RecyclerView.ViewHolder{
    private TextView title;
    private TextView date;
    private TextView from;
    private TextView to;
    private TextView category;
    private TextView attach;

    public UnsortedViewHolder(@NonNull View itemView) {
        super(itemView);
        title = itemView.findViewById(R.id.tv_title);
        date = itemView.findViewById(R.id.tv_date);
        from = itemView.findViewById(R.id.tv_from2);
        to = itemView.findViewById(R.id.tv_to2);
        category = itemView.findViewById(R.id.tv_category);
        attach = itemView.findViewById(R.id.tv_attach);
    }
}

And the second, new one:

    List<Unsorted> list = new ArrayList<>();

@NonNull
@Override
public UnsortedViewHolder2 onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    View itemView = LayoutInflater.from(parent.getContext())
            .inflate(R.layout.tasks2_layout , parent, false);
    return new  UnsortedAdapter2.UnsortedViewHolder2(itemView);
}

@Override
public void onBindViewHolder(@NonNull UnsortedViewHolder2 holder, int position) {
    Unsorted data = list.get(position);
    holder.title.setText(data.getName());
    holder.date.setText(data.getDate());
    holder.category.setText(String.valueOf(data.getCategory()));
    holder.attach.setText(String.valueOf(data.isAttach()));
    holder.to.setText(String.valueOf(toTime(data.getDuration() + data.getTimeBegin())));
    holder.from.setText(String.valueOf(toTime(data.getTimeBegin())));
}

public void setData1(List<Unsorted> unsortedList){
    this.list = unsortedList;
    notifyDataSetChanged();
}

@Override
public int getItemCount() {
    return list.size();
}

class UnsortedViewHolder2 extends RecyclerView.ViewHolder{
    private TextView title;
    private TextView date;
    private TextView from;
    private TextView to;
    private TextView category;
    private TextView attach;

    public UnsortedViewHolder2(@NonNull View itemView) {
        super(itemView);
        title = itemView.findViewById(R.id.tv_title1);
        date = itemView.findViewById(R.id.tv_date1);
        from = itemView.findViewById(R.id.tv_from3);
        to = itemView.findViewById(R.id.tv_to3);
        category = itemView.findViewById(R.id.tv_category1);
        attach = itemView.findViewById(R.id.tv_attach1);
    }
}

When I have set a different adapter to each of the recyclerview, nothing changed. As in previous case, only second recyclerview was showing some data.

final UnsortedAdapter adapter = new UnsortedAdapter();
    eatFrog.setHasFixedSize(true);
    eatFrog.setLayoutManager(new LinearLayoutManager(this));
    eatFrog.setAdapter(adapter);
 final UnsortedAdapter2 adapter2 = new UnsortedAdapter();
    biologicalRhythms.setAdapter(adapter2);
    biologicalRhythms.setLayoutManager(new LinearLayoutManager(this));
    biologicalRhythms.setHasFixedSize(true);

And in onChange:

 adapter.setData(EatAFrog(unsorted));
 eatAFrogList = EatAFrog(unsorted);

 adapter2.setData1(BiologicalRhythms(unsorted));
 biologicalList = BiologicalRhythms(unsorted);

Could you please suggest how I can solve this problem? Thanks for any help.

MyViewModel class:

public class UnsortedViewModel extends AndroidViewModel {
private DatesRepository repository2;
private UnsortedRepository repository;
private SortedRepository repository3;
private LiveData<List<Unsorted>> allUnsorted;

public UnsortedViewModel(@NonNull Application application) {
    super(application);
    repository3 = new SortedRepository(application);
    repository2 = new DatesRepository(application);
    repository = new UnsortedRepository(application);
    allUnsorted = repository.getAllUnsorted();
}

public LiveData<List<Unsorted>> getUnsortedWhereDateIsAlgo1(String currentDate) throws ExecutionException, InterruptedException{
   return repository.getUnsortedWhereDateIs(currentDate);
}
public LiveData<List<Unsorted>> getUnsortedWhereDateIsAlgo2(String currentDate) throws ExecutionException, InterruptedException{
    return repository.getUnsortedWhereDateIs(currentDate);
}

MutableLiveData<List<Unsorted>> unsortedWhereDateIsAlgo1 = new MutableLiveData<>();
MutableLiveData<List<Unsorted>> unsortedWhereDateIsAlgo2 = new MutableLiveData<>();

public void insertDate(Dates dates) {
    repository2.insertDate(dates);
}

public LiveData<List<Unsorted>> getAllUnsorted() {
    return allUnsorted;
}

public void insert(Unsorted data){
    repository.insert(data);
}

public void deleteAllUnsorted(){
    repository.deleteAllUnsorted();
}

public void deleteWhereDateIs(String currentDate){
    repository.deleteWhereDateIs(currentDate);
}

public void insertSorted(Sorted data){
    repository3.insertSorted(data);
}
}

Repository:

public class UnsortedRepository {
private UnsortedDao unsortedDao;
private LiveData<List<Unsorted>> allUnsorted;

public UnsortedRepository(Application application){
    UnsortedDatabase database = UnsortedDatabase.getInstance(application);
    unsortedDao = database.unsortedDao();
    allUnsorted = unsortedDao.getAllUnsorted();
}


public LiveData<List<Unsorted>> getUnsortedWhereDateIs(String currentDate) 
throws ExecutionException, InterruptedException{
return new      
 GetUnsortedWhereDateIsAsyncTask(unsortedDao).execute(currentDate).get();
}

private static class GetUnsortedWhereDateIsAsyncTask extends 
       AsyncTask<String, Void, LiveData<List<Unsorted>>> {
private UnsortedDao unsortedDao;

private GetUnsortedWhereDateIsAsyncTask(UnsortedDao unsortedDao){
        this.unsortedDao = unsortedDao;
    }
@Override
protected LiveData<List<Unsorted>> doInBackground(String ... strings) {
LiveData<List<Unsorted>> list = 
unsortedDao.getUnsortedWhereDateIs(strings[0]);
return list;
    }
}
}

Dao:

@Query ("SELECT * FROM Unsorted WHERE date = :currentDate")
LiveData<List<Unsorted>> getUnsortedWhereDateIs (String currentDate);

Answer 1

Your problem is, that you are observing single data source, so you will always have same data in both adapters. You need to add another LiveData inside your viewmodel. Use something like this:

unsortedWhereDateIsAlgo1 : MutableLiveData<List<Unsorted>>()
unsortedWhereDateIsAlgo2 : MutableLiveData<List<Unsorted>>()

and post result of your algorithms into correct LiveData:

fun algo1() {
    //some code/operations
    unsortedWhereDateIsAlgo1.postValue(result)
}

fun algo2() {
    //some different code/operations
    unsortedWhereDateIsAlgo2.postValue(result)
}

Next, in your fragment/activity:

viewModel.getUnsortedWhereDateIsAlgo1(currentDate).observe(this, new Observer<List<Unsorted>>() {
    @Override
    public void onChanged(List<Unsorted> unsorted) {
        final UnsortedAdapter adapter = new UnsortedAdapter();
        adapter.setData(EatAFrog(unsorted));
        eatFrog.setHasFixedSize(true);
        eatFrog.setLayoutManager(new LinearLayoutManager(this));
        eatFrog.setAdapter(adapter);
    }
});

and

viewModel.getUnsortedWhereDateIsAlgo2(currentDate).observe(this, new Observer<List<Unsorted>>() {
    @Override
    public void onChanged(List<Unsorted> unsorted) {
        final UnsortedAdapter adapter2 = new UnsortedAdapter();
        adapter2.setData(BiologicalRhythms(unsorted));
        biologicalRhythms.setAdapter(adapter2);
        biologicalRhythms.setLayoutManager(new LinearLayoutManager(this));
        biologicalRhythms.setHasFixedSize(true);                           
    }
});