Can't find example - Use spinner to populate Textfield

package com.example.sqlite;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import androidx.annotation.Nullable;
import java.util.ArrayList;

import static android.content.ContentValues.*;

public class DatabaseHelper extends SQLiteOpenHelper {
    public static final String DATABASE_NAME = "student.db";
    public static final String TABLE_NAME = "student_table";
    public static final String COL_1 = "ID";
    public static final String COL_2 = "NAME";
    public static final String COL_3 = "SURNAME";
    public static final String COL_4 = "MARKS";

    public DatabaseHelper(@Nullable Context context) {
        super(context, DATABASE_NAME, null, 1);
        SQLiteDatabase db = this.getWritableDatabase();
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table " + TABLE_NAME +" (ID INTEGER PRIMARY KEY AUTOINCREMENT,NAME TEXT,SURNAME TEXT,MARKS INTEGER)");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS "+TABLE_NAME);
        onCreate(db);
    }

    public boolean insertData(String name,String surname,String marks) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(COL_2,name);
        contentValues.put(COL_3,surname);
        contentValues.put(COL_4,marks);
        long result = db.insert(TABLE_NAME,null ,contentValues);
        if(result == -1) return false;
        else
            return true;
    }

    public Cursor getAllData() {
        SQLiteDatabase db = this.getWritableDatabase();
        Cursor res = db.rawQuery("select * from "+TABLE_NAME,null);
        return res;
    }

    public boolean updateData(String id,String name,String surname,String marks) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(COL_1,id);
        contentValues.put(COL_2,name);
        contentValues.put(COL_3,surname);
        contentValues.put(COL_4,marks);
        db.update(TABLE_NAME, contentValues, "ID = ?",new String[] { id });
        return true;
    }

    public Integer deleteData (String id) {
        SQLiteDatabase db = this.getWritableDatabase();
        return db.delete(TABLE_NAME, "ID = ?",new String[] {id});
    }

    public ArrayList<String> getAllNames(){
        ArrayList<String> list=new ArrayList<String>();
        SQLiteDatabase db=this.getReadableDatabase();
        db.beginTransaction();
        String selectQuery="SELECT * FROM "+"student_table";
        Cursor cursor=db.rawQuery(selectQuery,null);
        if(cursor.getCount()>0){
            list.add(0,"SELECT NAME");
            while(cursor.moveToNext()){
                String personname = cursor.getString(cursor.getColumnIndex("NAME"));
                list.add(personname);
            }
        }
        db.setTransactionSuccessful();
        db.endTransaction();
        db.close();
        return list;
    }
}

package com.example.sqlite;

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

public class SpinnerActivity extends AppCompatActivity {
    DatabaseHelper myDb;
    EditText editName,editSurname,editMarks,editLoadsTemp;
    Spinner spinnerTestname;
  
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_spinner);

        myDb = new DatabaseHelper(this);
        Spinner testname=(Spinner)findViewById(R.id.spinner_testname);
      
        ArrayList<String> arrayList1=myDb.getAllNames();
        ArrayAdapter<String> arrayAdapter1=new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item, arrayList1);
        testname.setAdapter(arrayAdapter1);
        testname.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                Toast.makeText(SpinnerActivity.this,"You clicked on something!",Toast.LENGTH_LONG).show();
            }
            @Override
            public void onNothingSelected(AdapterView<?> parent) {
            }
        });

        editName = findViewById((R.id.editText_name));
        editSurname = findViewById((R.id.editText_surname));
        editMarks = findViewById((R.id.editText_marks));
        spinnerTestname = (Spinner)findViewById(R.id.spinner_testname);
    }
}