How to add Custom Spinner in Android?

package org.geeksforgeeks.demo;

public class Item {
    private String name;

    public Item(String name)
    {
        this.name = name;
    }

    public String getName()
    {
        return name;
    }
}

package org.geeksforgeeks.demo;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;
import java.util.ArrayList;

public class Adapter extends ArrayAdapter<Item> {

    public Adapter(Context context, ArrayList<Item> list) {
        super(context, 0, list);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        return initView(position, convertView, parent);
    }

    @Override
    public View getDropDownView(int position, View convertView, ViewGroup parent) {
        return initView(position, convertView, parent);
    }

    private View initView(int position, View convertView, ViewGroup parent) {
        // Inflate the view only if it's null to optimize performance
        if (convertView == null) {
            convertView = LayoutInflater.from(getContext()).inflate(R.layout.item_spinner, parent, false);
        }

        // Find TextView and set the item name
        TextView textViewName = convertView.findViewById(R.id.text_view);
        Item currentItem = getItem(position);

        if (currentItem != null) {
            textViewName.setText(currentItem.getName());
        }

        return convertView;
    }
}

package org.geeksforgeeks.gfgcustomspinner;

import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Spinner;
import android.widget.Toast;
import androidx.appcompat.app.AppCompatActivity;
import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    ArrayList<AlgorithmItem> algorithmItems;
    AlgorithmAdapter adapter;

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

        initList();
        Spinner spinner = findViewById(R.id.spinner_algorithm);

        // we pass our item list and context to our Adapter.
        adapter = new AlgorithmAdapter(this, algorithmItems);
        spinner.setAdapter(adapter);

        spinner.setOnItemSelectedListener(
            new AdapterView.OnItemSelectedListener() {
            
        @Override
        public void onItemSelected(AdapterView<?> parent, View view,
            int position, long id)
        {
            // It returns the clicked item.
            AlgorithmItem clickedItem = (AlgorithmItem)parent.getItemAtPosition(position);
                    
            String name = clickedItem.getAlgorithmName();
                
            Toast.makeText(MainActivity.this,name + " selected",
                            Toast.LENGTH_SHORT).show();
        }
                
        @Override
        public void onNothingSelected(AdapterView<?> parent)
        {}
        });
    }

    // It is used to set the algorithm names to our array
    // list.
    private void initList()
    {
        algorithmItems = new ArrayList<>();
        algorithmItems.add(new AlgorithmItem("Quick Sort"));
        algorithmItems.add(new AlgorithmItem("Merge Sort"));
        algorithmItems.add(new AlgorithmItem("Heap Sort"));
        algorithmItems.add(new AlgorithmItem("Prims Algorithm"));
        algorithmItems.add(new AlgorithmItem("Kruskal Algorithm"));
        algorithmItems.add(new AlgorithmItem("Rabin Karp"));
        algorithmItems.add(new AlgorithmItem("Binary Search"));
    }
}