1. activity_main.xml 코드

<androidx.appcompat.widget.LinearLayoutCompat
    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"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity"
    android:layout_margin="20dp">

    <TextView
        android:id="@+id/tvStart"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="선택을 시작하시겠습니까?" />
    <CheckBox
        android:id="@+id/cbStart"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="시작함 " />
    <TextView
        android:id="@+id/tvPet"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="좋아하는 애완동물은?"
        android:visibility="invisible"/>

    <RadioGroup
        android:id="@+id/rGroup1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:visibility="invisible">
        <RadioButton
            android:id="@+id/btnPuppy"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="강아지" />
        <RadioButton
            android:id="@+id/btnCat"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="고양이" />
        <RadioButton
            android:id="@+id/btnRabbit"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="토끼" />
    </RadioGroup>

    <Button
        android:id="@+id/btnEnd"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="선택 완료"
        android:visibility="invisible"/>
    <ImageView
        android:id="@+id/imgPet"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:srcCompat="@drawable/cat"
        android:visibility="invisible"/>

</androidx.appcompat.widget.LinearLayoutCompat>

2. MainActivity.java 코드

public class MainActivity extends AppCompatActivity {

    private TextView tvStart, tvPet;
    private CheckBox cbStart;
    private RadioGroup rGroup1;
    private RadioButton btnPuppy, btnCat, btnRabbit;
    private Button btnEnd;
    private ImageView imgPet;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setTitle("애완동물 사진 보기");

        init();
        initLr();
    }

    @Override
    public void init() {
        tvStart = findViewById(R.id.tvStart);
        tvPet = findViewById(R.id.tvPet);
        cbStart = findViewById(R.id.cbStart);
        rGroup1 = findViewById(R.id.rGroup1);
        btnPuppy = findViewById(R.id.btnPuppy);
        btnCat = findViewById(R.id.btnCat);
        btnEnd = findViewById(R.id.btnEnd);
        imgPet = (ImageView) findViewById(R.id.imgPet);
    }

    @Override
    public void initLr() {
        cbStart.setOnCheckedChangeListener(
            (buttonView, isChecked) -> {
                if(cbStart.isChecked() == true){
                    tvPet.setVisibility(View.VISIBLE);
                    rGroup1.setVisibility(View.VISIBLE);
                    btnEnd.setVisibility(View.VISIBLE);
                    imgPet.setVisibility(View.VISIBLE);
                } else {
                    tvPet.setVisibility(View.INVISIBLE);
                    rGroup1.setVisibility(View.INVISIBLE);
                    btnEnd.setVisibility(View.INVISIBLE);
                    imgPet.setVisibility(View.INVISIBLE);
                }
            }
        );
        btnEnd.setOnClickListener(new View.OnClickListener() {
            public void onClick(View arg0) {
                switch (rGroup1.getCheckedRadioButtonId()) {
                    case R.id.btnPuppy:
                        imgPet.setImageResource(R.drawable.puppy);
                        break;
                    case R.id.btnCat:
                        imgPet.setImageResource(R.drawable.cat);
                        break;
                    case R.id.btnRabbit:
                        imgPet.setImageResource(R.drawable.rabbit);
                        break;
                    default:
                        Toast.makeText(getApplicationContext(), "동물 먼저 선택하세요", 
                        		Toast.LENGTH_SHORT).show();
                }
            }
        });
    }
}