Null Error in Adapter

I'm trying to load a RecyclerViewwith data, but I get it NullPointerExceptionevery time I want to load the RecyclerView. (He RecyclerViewis shown in a Dialog). First, I have this clase:

public class FondosClase {
    private int recurso;
    private String nombre;

    public int getRecurso() {
        return recurso;
    }

    public void setRecurso(int recurso) {
        this.recurso = recurso;
    }

    public String getNombre() {
        return nombre;
    }

    public void setNombre(String nombre) {
        this.nombre = nombre;
    }

    public FondosClase(){}

    public FondosClase(int recurso, String nombre) {
        this.recurso = recurso;
        this.nombre = nombre;
    }
}

Then my adapter:

public class AdaptadorMenuIzq extends RecyclerView.Adapter<AdaptadorMenuIzq.ViewHolder>{
    private FondosClase[] fondosClaseArrayList;
    private Context context;

    public AdaptadorMenuIzq(FondosClase[] fondosClaseArrayList, Context context) {
        this.fondosClaseArrayList = fondosClaseArrayList;
        this.context = context;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View layoutInflater = LayoutInflater.from(parent.getContext()).inflate(R.layout.design_rv_bg_men_izq, parent, false);
        return new AdaptadorMenuIzq.ViewHolder(layoutInflater);
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        final FondosClase fondosClase = fondosClaseArrayList[position];
        holder.textView.setText(fondosClase.getNombre());
        holder.imageView.setImageResource(fondosClase.getRecurso());
    }


    @Override
    public int getItemCount() {
        return fondosClaseArrayList.length;
    }

    public static class ViewHolder extends RecyclerView.ViewHolder {
        public ImageView imageView;
        public TextView textView;
        public ViewHolder(@NonNull View itemView) {
            super(itemView);
            this.imageView = itemView.findViewById(R.id.imageView);
            this.textView = itemView.findViewById(R.id.textView);
        }
    }
}

Then create a class where I create the method for Dialog:

public class Alertas {
    private AdaptadorMenuIzq adaptadorMenuIzq;

    public void AlertaMenuIzquierdoFondo(Context context){
        LayoutInflater layoutInflater = LayoutInflater.from(context);
        Dialog anuncio = new Dialog(context, R.style.FondoDialog);
        final View view = layoutInflater.inflate(R.layout.alerta_fondo_tarjeta_cv_rv, null);
        final RecyclerView rv = view.findViewById(R.id.rv_tarjetas);
        FondosClase[] fondosClases = new FondosClase[]{
                new FondosClase(R.drawable.permanent_bg_a, "a"),
                new FondosClase(R.drawable.permanent_bg_b, "b")
        };
        adaptadorMenuIzq = new AdaptadorMenuIzq(fondosClases, context);
        rv.setHasFixedSize(true);
        rv.setLayoutManager(new LinearLayoutManager(context));
        rv.setAdapter(adaptadorMenuIzq);
        anuncio.setContentView(view);
        anuncio.show();
    }
}

And from my MainActivity I run it through a FAB:

    binding.appBarMain.fab.setOnClickListener(view ->{
                alertas = new Alertas();
                alertas.AlertaMenuIzquierdoFondo(MainActivity.this);
            }
    );

When I press the button to show it I get the following error:

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
    at com.frabasoft.genshinimpactrecursos.Adaptadores.AdaptadorMenuIzq.onBindViewHolder(AdaptadorMenuIzq.java:35)

The line that marks the error is the following:

holder.textView.setText(fondosClase.getNombre());

I changed it to:

holder.textView.setText(fondosClaseArrayList[position].geNombre());

But, the result was the same.

I attach the xml:

alert_fund_card_cv_rv:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    android:layout_gravity="center"
    app:cardCornerRadius="75dp"
    android:orientation="vertical"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_marginTop="25dp"
    android:layout_marginRight="25dp"
    android:layout_marginBottom="25dp"
    android:layout_marginLeft="25dp"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/rv_tarjetas"
        android:layout_marginTop="25dp"
        android:layout_marginRight="25dp"
        android:layout_marginBottom="25dp"
        android:layout_marginLeft="25dp"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
</RelativeLayout>

design_rv_bg_menu_izq:

<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView
    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"
    style="@style/CardView.Light"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_margin="3dp"
    android:elevation="5dp">
    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <ImageView
            android:id="@+id/ivIcon"
            android:layout_width="120dp"
            android:layout_height="120dp"
            android:src="@mipmap/ic_launcher"
            android:layout_margin="8dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />
        <TextView
            android:id="@+id/tvIcon"
            android:layout_width="120dp"
            android:layout_height="120dp"
            android:src="@mipmap/ic_launcher"
            android:layout_margin="8dp"
            android:text="HOLA"
            android:gravity="center"/>

    </LinearLayout>
</androidx.cardview.widget.CardView>

Can someone tell me what data I'm getting wrong?