Recyclerview Does not load on screen

Question

My Recycler view does not appear on the screen if anyone can help I’m a beginner so I’m struggling, but I managed to do two other only that is keeping me awake :/ Thank you very much =]

MY ADAPTER

public class DiasAdapter extends RecyclerView.Adapter<DiasAdapter.MyViewHolder> {
        ArrayList<Dia> dias;
        Context context;
        DiasListner diasListner;
//private RecyclerViewClickListener listener;


           public DiasAdapter(Context context, ArrayList<Dia> dias, DiasListner diasListner) {
            this.context = context;
            this.dias = dias;
            this.diasListner = diasListner;

        }


        //Aqui cria as visualizações
        @NonNull
        @Override
        public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
//Criação da view

            View view = LayoutInflater.from(parent.getContext())
                    .inflate(R.layout.item_dias, parent, false);
            return new MyViewHolder(view);
        }



    @Override
        public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {
        final Dia dia = dias.get(position);

        holder.imageCalendarioEnsaio.setImageResource(dia.getImgDias());

        holder.textViewDiasSemana.setText(dia.getNomeDias());

        //Pegando ação do clique do usuário na lista

//Pegando ação do clique do usuário na lista
        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                diasListner.addDia(dia );

            }
        });
//Seta imagem

        }

    @Override
    public long getItemId(int i) {
        return i;
    }




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


        //Esssa classe MY VIEWHOLDER é responsável por guardar os dados antes de eles serem exibidos na tela
        public class MyViewHolder extends RecyclerView.ViewHolder {
               //INICILIZA VARIAVEL
            ImageView imageCalendarioEnsaio;
            TextView textViewDiasSemana;


            public MyViewHolder(@NonNull View itemView) {
                super(itemView);

                imageCalendarioEnsaio = itemView.findViewById(R.id.imageCalendarioEnsaio);
                textViewDiasSemana = itemView.findViewById(R.id.textViewDiasSemana);
            }
        }
}

MY LISTENER

public interface DiasListner {
    public void addDia(Dia dia);
}

Main class

package com.example.tocacomigo;

import android.Manifest;
import android.app.DatePickerDialog;
import android.content.pm.PackageManager;
import android.location.Address;
import android.location.Geocoder;
import android.location.Location;
import android.os.Bundle;
import android.text.Html;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.recyclerview.widget.DefaultItemAnimator;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import com.example.tocacomigo.activity.Estilo;
import com.example.tocacomigo.adapter.DiasAdapter;
import com.example.tocacomigo.adapter.EstilosAdapter;
import com.example.tocacomigo.adapter.InstrumentosAdapter;
import com.example.tocacomigo.listner.DiasListner;
import com.example.tocacomigo.listner.EstilosListner;
import com.example.tocacomigo.listner.InstrumentoListner;
import com.example.tocacomigo.model.Musico;
import com.google.android.gms.location.FusedLocationProviderClient;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;

import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.List;
import java.util.Locale;

public class FinalizaCadastro extends AppCompatActivity implements InstrumentoListner, EstilosListner, DiasListner {

    //Recycler DIAS ENSAIO------------------------------------------
    RecyclerView recyclerViewDias;
    ArrayList<Dia> dias;
    DiasAdapter diasAdapter;
    private List<String> diasString;

    //Recycler ESTILOS MUSICAIS------------------------------------------
    RecyclerView recyclerViewEstilos;
    ArrayList<Estilo> estilos;
    EstilosAdapter estilosAdapter;
    private List<String> estilosString;


    //---------------------------INSTRUMENTOS-------------------------------------------
    RecyclerView recyclerViewInstrumentos;
    ArrayList<Instrumento> instrumentos;
    InstrumentosAdapter adapter_instrumentos;
    private List<String> instrumentosString;


    //Variaveis de Localização ------------
    Button btnLocalizacaoMusico, btnFinalizarCadastro;
    TextView textViewLocalizacao, textView1, textView2, textView4, textView6;
    FusedLocationProviderClient fusedLocationProviderClient;

    //----REFERENTE A DATA DE NASCIMENTO---------------
    Button btnCalendario;
    TextView textDataNasc, textIdade;

    //----------------FIREBASE----------
    private FirebaseAuth firebaseAuth;
    private FirebaseDatabase database;


    private Musico musico;


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


        //----FIREBASE-----------------------------------

        database = FirebaseDatabase.getInstance();


        //-----------------------------------------------------------ESTILOS---------------------
        recyclerViewEstilos = findViewById(R.id.recyclerEstilos);
        recyclerViewDias = findViewById(R.id.recyclerViewDias);
        recyclerViewInstrumentos = findViewById(R.id.recyclerViewInstrumentos);


        //---------------------CRIANDO STRING DE ARRAYS DE ESTILOS ------


        String[] nomeEstilo = {"Axé", "Black Music", "Blues", "Bossa Nova", "Chillout", "Classic Rock", "Clássico", "Country", "Dance", "Disco", "Electro Swing", "Electronica", "Emocore", "Fado", "Folk", "Forró", "Funk", "Funk Carioca", "Gospel/Religioso", "Gótico", "Grunge", "Hard Rock", "Hardcore", "Heavy Metal", "Hip Hop", "House", "Indie", "industrial", "infantil", "instrumental", "j-pop", "Jazz", "jovem Guarda", "K Pop", "Kizomba", "Metal", "MPB", "Músicas Gaúchas", "New Age", "New Wave", "Pagode", "Paino Rock", "Pop", "Pop/Funk", "Pop/Rock", "Pós Punk", "Post Rock", "Power Pop", "Progressivo", "Psicodelia", "Punk Rock", "R&B", "Rap", "Reggae", "Reggaeton", "Regional", "Rock", "Rock Alternativo", "Rockabilly", "Romântico", "Samba", "Samba Enredo", "Sertanejo", "Ska", "Soft Rock", "Soul Music", "Surf Music", "Tecnopop", "Trance", "Trap", "Trilha Sonora", "Trip Hop", "Tropical House", "Velha Guarda", "World Music",
        };


        //---------------------------ESTILO--------------------------------------------------
        //Inicializando o arrayList

        estilos = new ArrayList<>();
        for (int i = 0; i < nomeEstilo.length; i++) {
            Estilo estiloM = new Estilo(nomeEstilo[i]);
            estilos.add(estiloM);
        }

        //Design horizontal ESTILO-------------------------------------------

        LinearLayoutManager layoutManagerEstiloM = new LinearLayoutManager(
                FinalizaCadastro.this, LinearLayoutManager.VERTICAL, false
        );

        recyclerViewEstilos.setLayoutManager(layoutManagerEstiloM);
        recyclerViewEstilos.setItemAnimator(new DefaultItemAnimator());

        //Inicializa EstilosAdapter------------------------------------------------ESTILOS

        estilosAdapter = new EstilosAdapter(FinalizaCadastro.this, estilos, this);
        //Seta adapter para RecyclerView

        recyclerViewEstilos.setAdapter(estilosAdapter);


        musico = getIntent().getParcelableExtra("musico");

        //Localização
        btnLocalizacaoMusico = findViewById(R.id.btnLocalizacaoMusico);
        btnFinalizarCadastro = findViewById(R.id.btnFinalizarCadastro);

        textViewLocalizacao = findViewById(R.id.textViewLocalizacao);
        textView1 = findViewById(R.id.textView1);
        textView2 = findViewById(R.id.textView2);
        textView4 = findViewById(R.id.textView4);
        textView6 = findViewById(R.id.textView6);
        //Informaçoes de latitude e longitude por enquanto deixei invisiveis
        textView1.setVisibility(View.GONE);
        textView2.setVisibility(View.GONE);
        textView4.setVisibility(View.GONE);
        textView6.setVisibility(View.GONE);

        instrumentosString = new ArrayList<>();
        estilosString = new ArrayList<>();
        diasString = new ArrayList<>();

        //Incializando fusedLocationProviderClient

        fusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this);

        btnLocalizacaoMusico.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                //Checar Permissoes

                if (ActivityCompat.checkSelfPermission(FinalizaCadastro.this
                        , Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
                    //permissão concedida

                    getLocation();

                } else {
                    //Permissão negada
                    ActivityCompat.requestPermissions(FinalizaCadastro.this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, 44);

                }
            }
        });
    }


    private void getLocation() {
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            // TODO: Consider calling
            //    ActivityCompat#requestPermissions
            // here to request the missing permissions, and then overriding
            //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
            //                                          int[] grantResults)
            // to handle the case where the user grants the permission. See the documentation
            // for ActivityCompat#requestPermissions for more details.
            return;
        }
        fusedLocationProviderClient.getLastLocation().addOnCompleteListener(new OnCompleteListener<Location>() {
            @Override
            public void onComplete(@NonNull Task<Location> task) {


                //Inicializa a localizacao

                Location location = task.getResult();

                if (location != null) {

                    try {

                        //Inicializa geoCoder

                        Geocoder geocoder = new Geocoder(FinalizaCadastro.this, Locale.getDefault());

                        //Inicializa lista de endereço


                        List<Address> address = geocoder.getFromLocation(
                                location.getLatitude(), location.getLongitude(), 1
                        );

//Seta a  latitude no textvIEW
                        textView1.setText(Html.fromHtml(
                                "<font color='#6200EE'><b>Latitude :</b><br></font>"
                                        + address.get(0).getLatitude()));
                        //Set Longitude
                        textView2.setText(Html.fromHtml(
                                "<font color='#6200EE'><b>Longitude :</b><br></font>"
                                        + address.get(0).getLongitude()));


                        //seta o país
                        textView4.setText(Html.fromHtml(
                                "<font color='#6200EE'><b>País :</b><br></font>"
                                        + address.get(0).getCountryName()


                        ));

                        //seta o local
                        textView6.setText(Html.fromHtml(
                                "<font color='#6200EE'><b>Local:</b><br></font>"
                                        + address.get(0).getLocality()


                        ));

                        //Seta  o endereço
                        textViewLocalizacao.setText(Html.fromHtml(
                                "<font color='#6200EE'><br></font>"
                                        + address.get(0).getAddressLine(0)


                        ));


                    } catch (IOException e) {
                        e.printStackTrace();


                    }
                }
            }
        });


//Este
        btnFinalizarCadastro.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                FirebaseDatabase mDatabase = FirebaseDatabase.getInstance();
                DatabaseReference myRef = mDatabase.getReference("musicos");

                String uuid = new SimpleDateFormat("yyyyMMddHHmmssSS").format(new Date());
                musico.setInstrumentos(instrumentosString);
                musico.setEstilos(estilosString);

                Task<Void> users = myRef.child("users").child(uuid).setValue(musico);

                users.addOnFailureListener(new OnFailureListener() {
                    @Override
                    public void onFailure(@NonNull Exception e) {
                        Log.d("Test", e.getMessage());
                    }
                });

                users.addOnSuccessListener(new OnSuccessListener<Void>() {
                    @Override
                    public void onSuccess(Void aVoid) {
                        Log.d("Test", "s");
                    }
                });

            }
        });


//----------------------------------------------------------------------
        textDataNasc = (TextView) findViewById(R.id.textDataNasc);
        textIdade = (TextView) findViewById(R.id.textIdade);

        //Evento do Clique do botão calendário
        btnCalendario = (Button) findViewById(R.id.btnCalendario);
        btnCalendario.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                pegaraData();

            }
        });


        // btn_deslogar = (Button) findViewById(R.id.btnDeslogar);
        //   btn_deslogar.setOnClickListener(this);


//---------
        Integer[] imgInstrumentos = {
                R.drawable.ic_baixo,
                R.drawable.ic_guitarra,
                R.drawable.ic_bateria,
                R.drawable.ic_vocalista,
                R.drawable.ic_teclado};

        String[] nomeInstrumento = {"baixo", "guitarra", "bateria", "vocalista", "tecladista"};

//----------------------------DIAS-----------------------------

        Integer[] imgDias = {
                R.drawable.ic_calendariodias,
                R.drawable.ic_filtrarmusico,
                R.drawable.ic_foto,
                R.drawable.ic_fotogaleria,
                R.drawable.ic_foto,
                R.drawable.ic_addusuario,
                R.drawable.ic_senha};

        String[] nomeDias = {"segunda", "terça", "quarta", "quinta", "sexta", "sábado", "domingo"};


        //Inicializar arraylist
        dias = new ArrayList<>();

       for (int i = 0; i < imgDias.length; i++) {
           Dia diasMusico = new Dia(imgDias[i], nomeDias[i]);
           dias.add(diasMusico);
        }


        //Layout Horizontal dos dias

        LinearLayoutManager layoutManagerDias = new LinearLayoutManager(
               FinalizaCadastro.this, LinearLayoutManager.HORIZONTAL, false
        );

       recyclerViewDias.setLayoutManager(layoutManagerDias);
       recyclerViewDias.setItemAnimator(new DefaultItemAnimator());

        //inicializa adapter

//Seta o adapater no recyclerviwq
        recyclerViewDias.setAdapter(diasAdapter);


        //Inicializar array
        instrumentos = new ArrayList<>();

        for (int i = 0; i < imgInstrumentos.length; i++) {
            Instrumento instrumentosMusico = new Instrumento(imgInstrumentos[i], nomeInstrumento[i]);
            instrumentos.add(instrumentosMusico);
        }

        // Layout horizontal dos instrumentos

        LinearLayoutManager layoutManager = new LinearLayoutManager(
                FinalizaCadastro.this, LinearLayoutManager.HORIZONTAL, false
        );

        recyclerViewInstrumentos.setLayoutManager(layoutManager);
        recyclerViewInstrumentos.setItemAnimator(new DefaultItemAnimator());


        //inicializa adapter
        adapter_instrumentos = new InstrumentosAdapter(FinalizaCadastro.this, instrumentos, this);
        diasAdapter = new DiasAdapter(FinalizaCadastro.this, dias,this);
        //Configuração RecyclerView dos Instrumentos
        recyclerViewInstrumentos.setAdapter(adapter_instrumentos);



    }
    //VER


    //    ---------------------------------------------------------------------------------------------------
//Aqui é para pegar a data do calendário referente ao nascimento do usuário

    private void pegaraData() {
        Calendar calendario = Calendar.getInstance();
        int dia = calendario.get(Calendar.DAY_OF_MONTH);
        int mes = calendario.get(Calendar.MONTH);
        int ano = calendario.get(Calendar.YEAR);


        //Criação do Objeto aqui eu pego as datas e exibo para o usuario

        DatePickerDialog datePickerDialog = new DatePickerDialog(FinalizaCadastro.this,
                new DatePickerDialog.OnDateSetListener() {
                    @Override
                    public void onDateSet(DatePicker datePicker, int year, int month, int dayOfMonth) {

                        textDataNasc.setText(dayOfMonth + "/" + (month + 1) + "/" + year);
                        //Calcular idade

                        calcularIdade(dayOfMonth, month, year);


                    }
                }, ano, mes, dia);

        datePickerDialog.show();
    }


    //Calcula idade
    private void calcularIdade(int diaNasc, int mesNasc, int anoNasc) {

        Calendar calendario = Calendar.getInstance();
        int diaAtual = calendario.get(Calendar.DAY_OF_MONTH);
        int mesAtual = calendario.get(Calendar.MONTH);
        int anoAtual = calendario.get(Calendar.YEAR);

        //Verifinado a idade do músico

        int idade = anoAtual - anoNasc;

        if (mesNasc > mesAtual) {
            idade--;
        } else if (mesAtual == mesNasc) {
            if (diaNasc > diaAtual) {
                idade--;
            }
        }

        textIdade.setText("Sua idade: " + idade);
    }

//--------------------------------------------------------------------------

    // Vai informar que o usuário selcionou um instrumento
    @Override
    public void addInstrumento(Instrumento instrumento) {

        // Verifica se o item clicado já existe eu removo e sai da função
        for (String item : this.instrumentosString) {
            if (item.equals(instrumento.getNomeInstrumento())) {
                this.instrumentosString.remove(item);
                return;
            }
        }

        initInstrumentosListString();
        this.instrumentosString.add(instrumento.nomeInstrumento);
    }

    private void initInstrumentosListString() {
        if (instrumentosString == null) {
            instrumentosString = new ArrayList<>();
        }
    }

//---------------------FAZENDO ESTILOS

    public void addEstilo(Estilo estilo) {

        // Verifica se o item clicado já existe eu removo e sai da função
        for (String item : this.estilosString) {
            if (item.equals(estilo.getNomeEstilo())) {
                this.estilosString.remove(item);
                return;
            }
        }

        initEstilosListString();
        this.estilosString.add(estilo.nomeEstilo);
    }

    private void initEstilosListString() {
        if (estilosString == null) {
            estilosString = new ArrayList<>();
        }
    }

    //------------------------DIAS

    public void addDia(Dia dia) {

        // Verifica se o item clicado já existe eu removo e sai da função
        for (String item : this.diasString) {
            if (item.equals(dia.getNomeDias())) {
                this.diasString.remove(item);
                return;
            }
        }

        initDiasListString();
        this.diasString.add(dia.nomeDias);

    }

    private void initDiasListString() {
        if (diasString == null) {
            diasString = new ArrayList<>();
        }
    }
}

MY ITEM DAYS

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical">

    <LinearLayout
        android:id="@+id/recyclerViewDias"
        android:layout_width="101dp"
        android:layout_height="117dp"
        android:layout_marginEnd="10dp"
        android:gravity="center"
        android:orientation="vertical"
        android:paddingStart="10dp">


        <ImageView
            android:id="@+id/imageCalendarioEnsaio"
            android:layout_width="73dp"
            android:layout_height="66dp"
            android:src="@drawable/foto" />

        <TextView
            android:id="@+id/textViewDiasSemana"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:gravity="center"
            android:text="Dias"
            android:textSize="10sp">
        </TextView>
    </LinearLayout>
</RelativeLayout>

MY DAY CLASS

package com.example.tocacomigo;

public class Dia {
        String nomeDias;
        Integer imgDias;


        public Dia(Integer imgDias, String nomeDias) {
            this.imgDias = imgDias;
            this.nomeDias = nomeDias;
        }

        public Integer getImgDias() {
            return imgDias;
        }

        public String getNomeDias() {
            return nomeDias;
        }
    }

Answer 1

You are setting the Adapter before starting it.

In line 325 you arrow the diasAdapter in the recyclerViewDias:

//Seta o adapater no recyclerview
recyclerViewDias.setAdapter(diasAdapter);

However Adapter is only started on line 348. Try to start class diasAdapter before setting it on recyclerViewDias.