안드로이드 질문!(간단한 편)

게시물 수정 , 삭제는 로그인 필요

왜 오류가 계속 뜨는지 모르겠습니다... 분명히 책에는 이렇게 된다고 했는데, 오류만 떠서 질문합니다!

package com.cookandroid.my325;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

EditText edit1, edit2;
Button btnAdd, btnSub, btnMul, btnDiv;
TextView textResult;
String num1, num2;


@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getSupportActionBar().setDisplayShowHomeEnabled(true);
getSupportActionBar().setIcon(R.drawable.u);
setTitle("초간단 계산기");

edit1 = (EditText) findViewById(R.id.Edit1);
edit2 = (EditText) findViewById(R.id.Edit2);

btnAdd = (Button) findViewById(R.id.BtnAdd);
btnSub = (Button) findViewById(R.id.BtnSub);
btnMul = (Button) findViewById(R.id.BtnMul);
btnDiv = (Button) findViewById(R.id.BtnDiv);

textResult = (TextView) findViewById(R.id.TextResult);

btnAdd.setOnTouchListener(new View.OnTouchListener() {
public boolean onTouch(View arg0, MotionEvent arg1) {
num1 = edit1.getText().toString();
num2 = edit2.getText().toString();
RESULT_OK = Integer.parseInt(num1) + Integer.parseInt(num2);
textResult.setText("계산 결과 : " + RESULT_OK.toString());
return false;
}
});

btnSub.setOnTouchListener(new View.OnTouchListener() {
public boolean onTouch(View arg0, MotionEvent arg1) {
num1 = edit1.getText().toString();
num2 = edit2.getText().toString();
result = Integer.parseInt(num1) - Integer.parseInt(num2);
textResult.setText("계산 결과 : " + result.toString());
return false;
}
});

btnMul.setOnTouchListener(new View.OnTouchListener() {
public boolean onTouch(View arg0, MotionEvent arg1) {
num1 = edit1.getText().toString();
num2 = edit2.getText().toString();
result = Integer.parseInt(num1) * Integer.parseInt(num2);
textResult.setText("계산 결과 : " + result.toString());
return false;
}
});

btnDiv.setOnTouchListener(new View.OnTouchListener() {
public boolean onTouch(View arg0, MotionEvent arg1) {
num1 = edit1.getText().toString();
num2 = edit2.getText().toString();
result = Integer.parseInt(num1) / Integer.parseInt(num2);
textResult.setText("계산 결과 : " + result.toString());
return false;
}
});
}
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">

<EditText
android:id="@+id/Edit1"
android:layout_weight="1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:hint="숫자1" />

<EditText
android:id="@+id/Edit2"
android:layout_weight="1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:hint="숫자2" />

<Button
android:id="@+id/BtnAdd"
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:text="더하기" />

<Button
android:id="@+id/BtnSub"
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:text="빼기" />

<Button
android:id="@+id/BtnMul"
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:text="곱하기" />
<Button
android:id="@+id/BtnDiv"
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:text="나누기" />

<TextView
android:id="@+id/TextResult"
android:layout_weight="1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:text="계산 결과 : "
android:textColor="#FF0000"
android:textSize="30dp" />

</LinearLayout>