Using list view and array adapter in android studio

I am a beginner in Android studio and I am trying to send an array list to a list view. I know that I am passing the correct info from my main activity to the second activity and that it is received properly in the second activity. My issue is coming in when I try to pass the array list "filteredlist" to the array adapter "arradapter" to then send to list view. It is giving me this error: java.lang.NullPointerException: "Attempt to invoke virtual method 'void android.widget.ListView.setAdapter(android.widget.ListAdapter)' on a null object reference." I am sure I am missing something, but I am not sure what. I am aware the code isn't perfect, and I plan on streamlining it later.

Second activity:

package com.example.charityfinder;

import android.os.Bundle;
import androidx.appcompat.app.AppCompatActivity;

import android.util.Log;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import java.util.ArrayList;



public class ResultsActivity extends AppCompatActivity {


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

        ArrayList<NationalCharity> filteredlist = (ArrayList<NationalCharity>) getIntent().getSerializableExtra("Filtered List");
        Log.d("DEBUG", "Second Activity: " + filteredlist);//prints out list here
        ListView dataresults = (ListView) findViewById(R.id.dataresults);
        ArrayAdapter<NationalCharity> arradapter = new ArrayAdapter<NationalCharity>(this, R.layout.item_view, R.id.itemTextView, filteredlist);
        dataresults.setAdapter(arradapter);


    }
}

Main Activity:

package com.example.charityfinder;

import android.content.Intent;
import android.os.Bundle;
import android.os.Parcelable;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.RadioButton;
import androidx.appcompat.app.AppCompatActivity;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Serializable;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.List;


public class MainActivity extends AppCompatActivity {

    //references to buttons and other controls

    Button submitbtn;
    RadioButton medicalRadio, envirRadio, hserviceRadio, educationRadio, publicaRadio,
            cultureRadio, domesticvRadio, hrightsRadio, homelessRadio, religionRadio, youthRadio;


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


        readcharitydata();

        medicalRadio = findViewById(R.id.medicalRadio);
        envirRadio = findViewById(R.id.envirRadio);
        hserviceRadio = findViewById(R.id.hserviceRadio);
        educationRadio = findViewById(R.id.educationRadio);
        publicaRadio = findViewById(R.id.publicaRadio);
        cultureRadio = findViewById(R.id.cultureRadio);
        domesticvRadio = findViewById(R.id.domesticvRadio);
        hrightsRadio = findViewById(R.id.hrightsRadio);
        homelessRadio = findViewById(R.id.homelessRadio);
        religionRadio = findViewById(R.id.religionRadio);
        youthRadio = findViewById(R.id.youthRadio);
        submitbtn = findViewById(R.id.submitbtn);
        submitbtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                openNewActivity();
            }
        });

    }

    String category;

    public void onRadioButtonClicked(View view) {

        if (medicalRadio.isChecked()) {
            category = "Medical";
        } else if (envirRadio.isChecked()) {
            category = "Environmental_Animal";
        } else if (hserviceRadio.isChecked()) {
            category = "Human_Services";
        } else if (educationRadio.isChecked()) {
            category = "Education";
        } else if (publicaRadio.isChecked()) {
            category = "Public_Affairs";
        } else if (cultureRadio.isChecked()) {
            category = "Culture_Arts_Humanities";
        } else if (domesticvRadio.isChecked()) {
            category = "Domestic_Violence";
        } else if (hrightsRadio.isChecked()) {
            category = "Human_Rights";
        } else if (homelessRadio.isChecked()) {
            category = "Homelessness";
        } else if (religionRadio.isChecked()) {
            category = "Religious";
        } else if (youthRadio.isChecked()) {
            category = "Youth";
        }

        filterCharity(category);
    }

    private List<NationalCharity> charities = new ArrayList<>();

    private void readcharitydata() {
        InputStream is = getResources().openRawResource(R.raw.charities);
        BufferedReader reader = new BufferedReader(new InputStreamReader(is, Charset.forName("UTF-8")));

        String line = "";
        try {
            //ignore headers
            reader.readLine();
            while ((line = reader.readLine()) != null) {
                //split by comma
                String[] token = line.split(",");
                //Read data
                NationalCharity charity = new NationalCharity();
                charity.setCharity_name(token[0]);
                charity.setCategory(token[1]);
                charity.setWeb_address(token[2]);
                charity.setAddress(token[3]);
                charity.setCity(token[4]);
                charity.setState(token[5]);
                charity.setZipcode(token[6]);
                charity.setMission_statement(token[7]);
                charities.add(charity);
            }
        } catch (IOException e) {
            Log.wtf("Error", "Error reading data file" + line, e);
            e.printStackTrace();
        }

    }

    private ArrayList<NationalCharity> filtered = new ArrayList<>();

    //needing to filter here from the charities list
    private void filterCharity(String type) {
        for (NationalCharity charity : charities) {
            if (charity.getCategory().equals(type)) {
                filtered.add(charity);
                Log.d("DEBUG", "Just created: " + filtered);
            }
        }

    }

    public void openNewActivity() {
        Intent intent = new Intent(MainActivity.this, ResultsActivity.class);
        intent.putExtra("Filtered List", filtered);
        Log.d("DEBUG", "Passing: " + filtered);
        startActivity(intent);
    }


}