[Android Studio] 간단한 계산기

 

MainActivity.java

0.00MB

activity_main.xml

0.00MB

더하기, 빼기, 나누기, 곱하기, 나머지를 구하는 계산기이다.

 

try ~ catch 문을 사용하고 계산값이 비어있거나 계산이 되지않을 때에 토스트를 출력한다.

 

 

• activity_main.xml

?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="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    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:hint="숫자2"
        android:layout_margin="10dp"
         />

    <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/BtnMul"
        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"
        />

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

    <TextView
        android:id="@+id/TextResult"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="30dp"
        android:textColor="#00BCD4"
        android:layout_margin="10dp"
        android:text="결과 :" />
</LinearLayout>

 

• mainActivity.java

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

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

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

        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);
        btnNa = (Button) findViewById(R.id.BtnNa);
        textResult = (TextView) findViewById(R.id.TextResult);


        btnAdd.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                    num1 = edit1.getText().toString();
                    num2 = edit2.getText().toString();

                    if(num1.isEmpty() || num2.isEmpty()) {
                        Toast.makeText(getApplicationContext(), "숫자를 입력하세요", Toast.LENGTH_SHORT).show();
                    }
                    else {
                        result = Integer.parseInt(num1) + Integer.parseInt(num2);
                        textResult.setText("계산 결과 : " + result.toString());
                    }
            }
        });


        btnSub.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                num1 = edit1.getText().toString();
                num2 = edit2.getText().toString();
                if (num1.isEmpty() || num2.isEmpty()) {
                    Toast.makeText(getApplicationContext(), "숫자를 입력하세요", Toast.LENGTH_SHORT).show();
                } else {
                    result = Integer.parseInt(num1) - Integer.parseInt(num2);
                    textResult.setText("계산 결과 : " + result.toString());
                }
            }
        });

        btnMul.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                num1 = edit1.getText().toString();
                num2 = edit2.getText().toString();
                if(num1.isEmpty() || num2.isEmpty()) {
                    Toast.makeText(getApplicationContext(), "숫자를 입력하세요", Toast.LENGTH_SHORT).show();
                }
                else {
                    result = Integer.parseInt(num1) * Integer.parseInt(num2);
                    textResult.setText("계산 결과 : " + result.toString());
                }
            }
        });

        btnDiv.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                num1 = edit1.getText().toString();
                num2 = edit2.getText().toString();
                if (num1.isEmpty() || num2.isEmpty()) {
                    Toast.makeText(getApplicationContext(), "숫자를 입력하세요", Toast.LENGTH_SHORT).show();
                } else {
                    result = Integer.parseInt(num1) / Integer.parseInt(num2);
                    textResult.setText("계산 결과 : " + result.toString());
                }
            }
        });

        btnNa.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                num1 = edit1.getText().toString();
                num2 = edit2.getText().toString();
                String error = "숫자를 입력하세요";
                if (num1.trim().equals("") || num2.trim().equals("")) {
                    Toast.makeText(getApplicationContext(), error, Toast.LENGTH_SHORT).show();
                }
                else{
                try {
                    result = Integer.parseInt(num1) % Integer.parseInt(num2);
                    textResult.setText("계산 결과 : " + result.toString());


                } catch (java.lang.ArithmeticException e) {
                    Toast.makeText(getApplicationContext(), "계산이 되지않습니다", Toast.LENGTH_SHORT).show();
                }

                }
            }
        });



    }
}