Android_Java(3) - ImageView(pets)

//MainActivity.java

package kr.co.pets;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.ImageView;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    TextView textView1, textView2;
    CheckBox chkAgree;
    RadioGroup rGroup;
    RadioButton rdoDog, rdoCat, rdoRabbit;
    Button btnOK;
    ImageView imagePet;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        getSupportActionBar().setDisplayShowHomeEnabled(true);
        getSupportActionBar().setIcon(R.drawable.ic_launcher);
        setTitle("반려동물 사진 보기");

        //위젯을 변수에 대입
        textView1 = findViewById(R.id.textViewSta);
        chkAgree = findViewById(R.id.checbox);

        textView2 = findViewById(R.id.textViewCho);
        rGroup = findViewById(R.id.Rgroup);
        rdoDog = findViewById(R.id.RdoDog);
        rdoCat = findViewById(R.id.RdoCat);
        rdoRabbit = findViewById(R.id.RdoRabbit);

        btnOK = findViewById(R.id.buttonOK);
        imagePet = findViewById(R.id.imageView);

        //시작함 체크박스의 체크가 되면
        chkAgree.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
                //체크되면 위젯이 모두 보이도록 설정
                if(chkAgree.isChecked() == true){
                    textView2.setVisibility(View.VISIBLE);
                    rGroup.setVisibility(View.VISIBLE);
                    btnOK.setVisibility(View.VISIBLE);
                    imagePet.setVisibility(View.VISIBLE);
                }
                else{
                    textView2.setVisibility(View.INVISIBLE);
                    rGroup.setVisibility(View.INVISIBLE);
                    btnOK.setVisibility(View.INVISIBLE);
                    imagePet.setVisibility(View.INVISIBLE);
                }
            }
        });

        //선택완료 버튼을 클릭하면
        btnOK.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                switch (rGroup.getCheckedRadioButtonId()){
                    case R.id.RdoDog:
                        imagePet.setImageResource(R.drawable.dog3);
                        break;
                    case R.id.RdoCat:
                        imagePet.setImageResource(R.drawable.cat1);
                        break;
                    case R.id.RdoRabbit:
                        imagePet.setImageResource(R.drawable.rabbit2);
                        break;
                    default:
                        Toast.makeText(getApplicationContext(),"반려동물 먼저 선택하세요.",Toast.LENGTH_SHORT).show();
                }
            }
        });
    }
}

//activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    android:padding="20dp"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textViewSta"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="선택을 시작하겠습니까?"
        android:textSize="20dp" />

    <CheckBox
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/checbox"
        android:layout_weight="1"
        android:text="시작함" />

    <TextView
        android:id="@+id/textViewCho"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="좋아하는 애완동물은?"
        android:textSize="20dp"
        android:visibility="invisible"/>

    <RadioGroup
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/Rgroup"
        android:layout_weight="1"
        android:visibility="invisible">
        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/RdoDog"
            android:text="강아지"/>
        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/RdoCat"
            android:text="고양이"/>
        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/RdoRabbit"
            android:text="토끼"/>
    </RadioGroup>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/buttonOK"
        android:layout_weight="1"
        android:visibility="invisible"
        android:text="선택 완료"/>

    <ImageView
        android:layout_width="256dp"
        android:layout_height="256dp"
        android:id="@+id/imageView"
        android:layout_weight="1"
        android:visibility="invisible"/>


</LinearLayout>

<시작함 체크 시에 선택 사항 출력>

<좋아하는 애완동물을 체크하여, 선택완료 버튼 클릭시 사진이 출력됨>