안드로이드 개발 질문/답변

안드로이드 앱 실행시 강제종료 ㅠ ㅠ ㅠ

명재양 — Sun, 14 Mar 2021 11:08:16 +0900

코드는 이건데 숫자 입력후 더하기 누르면 강제종료되여,,,,뭘까요 선배님들 ㅠ_ㅠ

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">

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

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


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


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


<Button
android:id="@+id/BtnnMuI"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:text="곱하기"/>

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

<TextView
android:id="@+id/TextResult"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:text="계산결과:"
android:textColor="#000000"
android:textSize="30dp"/>


LinearLayout>

package com.example.myapplication;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.widget.Button;
import android.view.MotionEvent;
import android.view.View;
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;
Integer result;

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

setTitle("초간단계산기");
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.BtnnMuI);
btnDiv = (Button) findViewById(R.id.BtnDiv);
textResult = (TextView) findViewById(R.id.TextResult);

btnAdd.setOnTouchListener(new
View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent motionEvent) {
Num1 = edit1.getText().toString();
Num2 = edit2.getText().toString();
result = Integer.parseInt(Num1) +
Integer.parseInt(Num2);
textResult.setText("계산결과" + result.toString());
return false;
}
});

btnSub.setOnTouchListener(new
View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent motionEvent) {
Num1 = edit1.getText().toString();
Num2 = edit2.getText().toString();
result = Integer.parseInt(Num1) +
Integer.parseInt(Num2);
textResult.setText("계산결과" + result.toString());
return false;
}
});
btnMul.setOnTouchListener(new
View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent motionEvent) {
Num1 = edit1.getText().toString();
Num2 = edit2.getText().toString();
result = Integer.parseInt(Num1) +
Integer.parseInt(Num2);
textResult.setText("계산결과" + result.toString());
return false;
}
});
btnDiv.setOnTouchListener(new
View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent motionEvent) {
Num1 = edit1.getText().toString();
Num2 = edit2.getText().toString();
result = Integer.parseInt(Num1) +
Integer.parseInt(Num2);
textResult.setText("계산결과" + result.toString());
return false;
}
});
}}

안드로이드 앱 실행시 강제종료 ㅠ ㅠ ㅠ

명재양 — Sun, 14 Mar 2021 08:28:50 +0900

안드로이드 스튜디오로 계산기 만들어서

실행했는데 버튼은 다나오는데 버튼을 누르면 강제 종료되는데

뭐가문제일까요 ㅠㅠ

D/AndroidRuntime: Shutting down VM

E/AndroidRuntime: FATAL EXCEPTION: main

Process: com.example.myapplication, PID: 11747

java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference

at com.example.myapplication.MainActivity$1.onTouch(MainActivity.java:45)

at android.view.View.dispatchTouchEvent(View.java:14305)

at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3118)