How to implement Firebase Recycler Adapter in newer version of Android 3.1 and higher?

Question

Basically, what I am trying to do is use a FirebaseRecyclerAdapter and populate the RecyclerView with my custom designed CardView. The code for newer versions has been changed and therefore, I tried implementing it but didn't work. This is the code I use to write a year ago, which worked fine and populated my RecyclerView:

FirebaseRecyclerAdapter<DataClass,DataViewHolder> FBRA= new FirebaseRecyclerAdapter<DataClass, DataViewHolder>(
            DataClass,
            R.layout.myCardView,
            DataViewHolder.class,
            databaseReference
    ) {
        @Override
        protected void populateViewHolder(DataViewHolder viewHolder, DataClass model, int position) {
            viewHolder.setTitle(model.gettitle());
            viewHolder.setDate(model.getDate());
        }
   }; 
  myRecyclerView.setAdapter(FBRA);

And now we have to use something like this, but the problem is this code is not populating my recyclerView (What changes do I need to make here to populate my recyclerView with my cardView?)

@Override
protected void onStart() {
    super.onStart();

    Query query = FirebaseDatabase.getInstance()
            .getReference()
            .child("Official_Services");

    FirebaseRecyclerOptions<ServiceClass> options = new FirebaseRecyclerOptions.Builder<ServiceClass>()
            .setQuery(query, ServiceClass.class)
            .build();

    FirebaseRecyclerAdapter<ServiceClass, ServiceViewHolder> FBRA = new FirebaseRecyclerAdapter<ServiceClass, ServiceViewHolder>(options) {

        @NonNull
        @Override
        public ServiceViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int i) {

            View view = LayoutInflater.from(HomeActivity.this).inflate(R.layout.service_card, parent, false);

            return new ServiceViewHolder(view);

        }

        @Override
        protected void onBindViewHolder(@NonNull ServiceViewHolder holder, int position, @NonNull ServiceClass model) {

            holder.setServiceName(model.getServiceName());

            holder.setServiceCaption(model.getServiceCaption());

        }

    };

    mServiceList.setAdapter(FBRA);

}

Here is my ViewHolder class:

public static class ServiceViewHolder extends RecyclerView.ViewHolder {

    public ServiceViewHolder(View itemView) {

        super(itemView);

        View mView = itemView;

    }

    public void setServiceName(String serviceName) {

        TextView sName = itemView.findViewById(R.id.serviceName);

        sName.setText(serviceName);

    }

    public void setServiceCaption(String serviceCaption) {

        TextView sCaption = itemView.findViewById(R.id.serviceCap);

        sCaption.setText(serviceCaption);
    }

}

And this is my Model class of getters and setters:

public class ServiceClass {

private String serviceName;
private String serviceCode;
private String serviceCaption;
private String serviceIconUrl;

public ServiceClass() {
}

public ServiceClass(String serviceName, String serviceCode, String serviceCaption, String serviceIconUrl) {
    this.serviceName = serviceName;
    this.serviceCode = serviceCode;
    this.serviceCaption = serviceCaption;
    this.serviceIconUrl = serviceIconUrl;
}

public String getServiceName() {
    return serviceName;
}

public String getServiceCode() {
    return serviceCode;
}

public String getServiceCaption() {
    return serviceCaption;
}

public String getServiceIconUrl() {
    return serviceIconUrl;
}

public void setServiceName(String serviceName) {
    this.serviceName = serviceName;
}

public void setServiceCode(String serviceCode) {
    this.serviceCode = serviceCode;
}

public void setServiceCaption(String serviceCaption) {
    this.serviceCaption = serviceCaption;
}

public void setServiceIconUrl(String serviceIconUrl) {
    this.serviceIconUrl = serviceIconUrl;
}

@Override
public String toString() {
    return "ServiceClass{" +
            "serviceName='" + serviceName + '\'' +
            ", serviceCode='" + serviceCode + '\'' +
            ", serviceCaption='" + serviceCaption + '\'' +
            ", serviceIconUrl='" + serviceIconUrl + '\'' +
            '}';
}
}

Now what changes do I need to do?

Here is my entire java file:

public class HomeActivity extends AppCompatActivity {

    private RecyclerView mServiceList;

    private FirebaseDatabase mDatabase;

    private DatabaseReference myRef;

    FirebaseRecyclerAdapter<ServiceClass, ServiceViewHolder> FBRA;

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

        BottomNavigationViewEx bottomNavigationViewEx = findViewById(R.id.navViewBar);

        bottomNavigationViewEx.enableAnimation(false);

        bottomNavigationViewEx.enableShiftingMode(false);

        bottomNavigationViewEx.setTextVisibility(false);

        Calligrapher calligrapher = new Calligrapher(this);

        calligrapher.setFont(this, "Helvetica.ttf", true);

        mServiceList = findViewById(R.id.serviceRV);

        mServiceList.setHasFixedSize(true);

        mServiceList.setLayoutManager(new LinearLayoutManager(this));

        mDatabase = FirebaseDatabase.getInstance();

        myRef = mDatabase.getReference().child("Official_Services");

    }

    @Override
    protected void onStart() {
        super.onStart();

        FBRA.startListening();

        Query query = myRef;

        FirebaseRecyclerOptions<ServiceClass> options = new FirebaseRecyclerOptions.Builder<ServiceClass>()
                .setQuery(query, ServiceClass.class)
                .build();

        FBRA = new FirebaseRecyclerAdapter<ServiceClass, ServiceViewHolder>(options) {

            @NonNull
            @Override
            public ServiceViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int i) {

                View view = LayoutInflater.from(HomeActivity.this).inflate(R.layout.service_card, parent, false);

                return new ServiceViewHolder(view);

            }

            @Override
            protected void onBindViewHolder(@NonNull ServiceViewHolder holder, int position, @NonNull ServiceClass model) {

                holder.setServiceName(model.getServiceName());

                holder.setServiceCaption(model.getServiceCaption());

            }

        };

        mServiceList.setAdapter(FBRA);



    }



    public static class ServiceViewHolder extends RecyclerView.ViewHolder {

        public ServiceViewHolder(View itemView) {

            super(itemView);

            View mView = itemView;

        }

        public void setServiceName(String serviceName) {

            TextView sName = itemView.findViewById(R.id.serviceName);

            sName.setText(serviceName);

        }

        public void setServiceCaption(String serviceCaption) {

            TextView sCaption = itemView.findViewById(R.id.serviceCap);

            sCaption.setText(serviceCaption);
        }

    }

}

Answer 1

In order to be able to display data from the Firebase realtime database you need to start listening for changes and for that you should add the following line of code in the onStart() method:

@Override
protected void onStart() {
    super.onStart();
    FBRA.startListening();
}

To stop listening foir changes you need add the following line of code in the onStop() method like this:

@Override
protected void onStop() {
    super.onStop();
    if(FBRA != null) {
        FBRA.stopListening();
    }
}

Please see my answer from this post where I have explained why you should remove the listener.

P.S. Please also don't forget to make the FBRA a global variable and remove FirebaseRecyclerAdapter<ServiceClass, ServiceViewHolder> from the declaration of the object.

Answer 2

This is more of an advice. If you want to continue using the old method to populate your recyclerview ie The "populateViewHolder" method instead of the new "onBindViewHolder" method just use this;

implementation 'com.firebaseui:firebase-ui:1.0.1'

instead of upgraded firebase-ui versions