Problems to list firebase data on android

Question

Good morning ! I’m having trouble listing data from a certain node in my application... when I list it as the codes below I get the following return from Exception: "com.google.firebase.database.Databaseexception: Can’t Convert Object of type java.lang.String to type com.ramattecgmail.Rafah.herdeirosapp.Models.Cardapio" as the error nçao informs which object exactly it can’t convert I couldn’t solve the problem. Below follows how is the structure in firebase:

xml lista_cardapio.

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout    xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/fundo_cardapio">


<TextView
    android:id="@+id/tv_refeicao_lista"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Refeição"
    app:layout_constraintTop_toTopOf="parent"
    android:layout_marginTop="16dp"
    android:layout_marginLeft="24dp"
    app:layout_constraintLeft_toLeftOf="parent"
    android:textSize="20sp"/>

<TextView
    android:id="@+id/tv_ingredientes_lista"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="O que teremos?"
    android:layout_marginTop="8dp"
    app:layout_constraintTop_toBottomOf="@+id/tv_refeicao_lista"
    android:layout_marginLeft="24dp"
    app:layout_constraintLeft_toLeftOf="parent" />

 </android.support.constraint.ConstraintLayout>

Activitycardapio.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.ramattecgmail.rafah.herdeirosapp.Activitys.CardapioActivity"
android:orientation="vertical">

<android.support.design.widget.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/AppTheme.AppBarOverlay">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:popupTheme="@style/AppTheme.PopupOverlay" />

</android.support.design.widget.AppBarLayout>

<ListView
    android:id="@+id/lv_cardapio"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:divider="@color/linha_cardapio"
    android:dividerHeight="0.3dp"/>


</LinearLayout>

Cardapio.java(models)

public class Cardapio {
//ATRIBUTOS
private String refeicao;
private String ingredientes;
private String data;

public Cardapio(){

}

public void salvarCardapio(){

    //Pegando o ano atual
    Date ano = Calendar.getInstance().getTime();
    DateFormat format = new SimpleDateFormat("yyyy");
    String anoRetiro = format.format(ano);

    //pegando o ano atual para salvar no nó retiro
    DatabaseReference reference = ConfiguracaoFirebase.getFirebaseReference();
    reference.child("RETIRO")
            .child(anoRetiro)
            .child("CARDAPIO")
            .child(getData())
            .child(getRefeicao())
            .setValue(this);

}

public String getRefeicao() {
    return refeicao;
}

public void setRefeicao(String refeicao) {
    this.refeicao = refeicao;
}

public String getIngredientes() {
    return ingredientes;
}

public void setIngredientes(String ingredientes) {
    this.ingredientes = ingredientes;
}

public String getData() {
    return data;
}

public void setData(String data) {
    this.data = data;
}

}

Cardapioadapter.java

public class CardapioAdapter extends ArrayAdapter<Cardapio> {
private ArrayList<Cardapio> arrayList;
private Context context;

public CardapioAdapter(@NonNull Context c, @NonNull ArrayList<Cardapio> objects) {
    super(c, 0, objects);
    this.arrayList = objects;
    this.context = c;
}

@NonNull
@Override
public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
    View view = null;

    //Validando e criando a lista
    if (arrayList != null){
        LayoutInflater inflater = (LayoutInflater) context.getSystemService(context.LAYOUT_INFLATER_SERVICE);

        //Montando a view a partir do XML
        view = inflater.inflate(R.layout.lista_cardapio, parent, false);

        //Recuperando os componentes para exibição
        TextView refeicao = view.findViewById(R.id.tv_refeicao_lista);
        TextView ingredientes = view.findViewById(R.id.tv_ingredientes_lista);

        Cardapio cardapio = arrayList.get(position);
        refeicao.setText(cardapio.getRefeicao());
        ingredientes.setText(cardapio.getIngredientes());

    }
    return view;
}
}

and last but not least, the Activity that should display the list Cardapioactivity.java

public class CardapioActivity extends AppCompatActivity {
//ATRIBUTOS
ListView listView;

private ArrayList<Cardapio> arrayList;
private ArrayAdapter adapter;
private DatabaseReference reference;
private ValueEventListener valueEventListener;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_cardapio);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);

    //INSTANCIANDO OS COMPONENTES
    arrayList = new ArrayList<>();
    listView = (ListView) findViewById(R.id.lv_cardapio);
    adapter = new CardapioAdapter(CardapioActivity.this, arrayList);
    listView.setAdapter(adapter);

    //Pegando o ano atual
    Date ano = Calendar.getInstance().getTime();
    DateFormat format = new SimpleDateFormat("yyyy");
    String anoRetiro = format.format(ano);

    reference = ConfiguracaoFirebase.getFirebaseReference()
            .child("RETIRO")
            .child(anoRetiro)
            .child("CARDAPIO")
            .child("24")
            .child("11")
            .child("Almoço");

    valueEventListener = new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            arrayList.clear();

            //Listando os eventos
            for (DataSnapshot data: dataSnapshot.getChildren()){
                Cardapio cardapio = data.getValue(Cardapio.class);
                arrayList.add(cardapio);
            }
            adapter.notifyDataSetChanged();
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    };
}

/******************************** METODOS ********************************/
@Override
protected void onStart() {
    super.onStart();
    reference.addValueEventListener(valueEventListener);
}

@Override
protected void onStop() {
    super.onStop();
    reference.removeEventListener(valueEventListener);
}

}

In the Ference it has the last Child ("Lunch") only for tests because what I want is to list all meals for the day I pass by parameter (in this case the 24 and the 11 will be passed dynamically)And if you observe you can see that in the Cardapio Model class where I do the recording through a dialogFragment I instate the date and firebase alone separates the day of the month on its nodes as image... Thanks in advance !

Answer 1

Apparently the problem was related to the fact that when I saved the data I didn’t add any kind of key, just pure data at the nodes, so I added an encryption precisely at the node that I needed to bring the children as picture:

So the same code presented above the account to bring the data of the cardapio that I needed, I answered for example, if someone has problems to list the data of firebase, maybe adding an encryption to the child node is enough if you’re listing them with dataSnapsho.getchildren