Cara Membuat Radio Button Android Studio

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="20sp"
        android:layout_centerHorizontal="true"
        android:text="@string/contoh_radio_button"
        android:textSize="25sp"
        android:textStyle="bold"/>

    <RadioGroup
        android:id="@+id/radioGroup"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/textView"
        android:layout_marginTop="20sp"
        android:layout_centerHorizontal="true">
        <RadioButton
            android:id="@+id/pria"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/pria"
            android:textSize="20sp"/>

        <RadioButton
            android:id="@+id/wanita"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/wanita"
            android:textSize="20sp"/>
    </RadioGroup>
</RelativeLayout>

package com.example.radiobutton;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.widget.RadioGroup;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

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

        RadioGroup radioGroup = (RadioGroup)findViewById(R.id.radioGroup);
        radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                if(checkedId == R.id.pria) {
                    Toast.makeText(getApplicationContext(), "Pilih Pria", Toast.LENGTH_SHORT).show();
                } else {
                    Toast.makeText(getApplicationContext(), "Pilih Wanita", Toast.LENGTH_SHORT).show();
                }
            }
        });
    }
}