android studio 계산기 #1

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<TableLayout 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:paddingRight="10dp"
    android:paddingLeft="10dp"
    android:paddingTop="50dp"
    android:stretchColumns="*"
    tools:context=".MainActivity">
 
    <TableLayout
        android:layout_height="0dp"
        android:layout_weight="1">
        <TableRow
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="0dp">
 
            <TextView
                android:id="@+id/et_result2"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:hint="this place is result"
                android:textSize="20sp" />
 
        </TableRow>
 
        <TableRow
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="0dp">
            <TextView />
 
        </TableRow>
 
        <TableRow
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="0dp">
            <TextView
                android:id="@+id/et_result"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textSize="20sp"
                android:hint="your cal space" />
 
        </TableRow>
 
        <TableRow
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="0dp">
            <TextView />
        </TableRow>
    </TableLayout>
 
    <TableLayout
        android:layout_height="0dp"
        android:layout_weight="5">
 
        <TableRow
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_weight="1">
            <Button
                android:id="@+id/btn_clear"
                android:layout_weight="1"
                android:layout_width="0dp"
                android:layout_height="match_parent"
                android:autoSizeTextType="uniform"
                android:text="C" />
            <TextView
                android:layout_width="10dp"
                android:layout_height="match_parent"/>
            <Button
                android:id="@+id/btn_left"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="match_parent"
                android:autoSizeTextType="uniform"
                android:text="(" />
            <TextView
                android:layout_width="10dp"
                android:layout_height="match_parent"/>
            <Button
                android:id="@+id/btn_right"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="match_parent"
                android:autoSizeTextType="uniform"
                android:text=")" />
            <TextView
                android:layout_width="10dp"
                android:layout_height="match_parent"/>
            <Button
                android:id="@+id/btn_per"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="match_parent"
                android:autoSizeTextType="uniform"
                android:text="%" />
        </TableRow>
 
        <TableRow
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_weight="1">
            <Button
                android:id="@+id/num_7"
                android:layout_weight="1"
                android:layout_width="0dp"
                android:layout_height="match_parent"
                android:autoSizeTextType="uniform"
                android:text="7" />
            <TextView
                android:layout_width="10dp"
                android:layout_height="match_parent"/>
            <Button
                android:id="@+id/num_8"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="match_parent"
                android:autoSizeTextType="uniform"
                android:text="8" />
            <TextView
                android:layout_width="10dp"
                android:layout_height="match_parent"/>
            <Button
                android:id="@+id/num_9"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="match_parent"
                android:autoSizeTextType="uniform"
                android:text="9" />
            <TextView
                android:layout_width="10dp"
                android:layout_height="match_parent"/>
            <Button
                android:id="@+id/btn_plus"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="match_parent"
                android:autoSizeTextType="uniform"
                android:text="+" />
        </TableRow>
 
        <TableRow
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_weight="1">
            <Button
                android:id="@+id/num_4"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="match_parent"
                android:autoSizeTextType="uniform"
                android:text="4" />
            <TextView
                android:layout_width="10dp"
                android:layout_height="match_parent"/>
            <Button
                android:id="@+id/num_5"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="match_parent"
                android:autoSizeTextType="uniform"
                android:text="5" />
            <TextView
                android:layout_width="10dp"
                android:layout_height="match_parent"/>
            <Button
                android:id="@+id/num_6"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="match_parent"
                android:autoSizeTextType="uniform"
                android:text="6" />
            <TextView
                android:layout_width="10dp"
                android:layout_height="match_parent"/>
            <Button
                android:id="@+id/btn_minus"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="match_parent"
                android:autoSizeTextType="uniform"
                android:text="-" />
        </TableRow>
 
        <TableRow
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_weight="1">
            <Button
                android:id="@+id/num_1"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="match_parent"
                android:autoSizeTextType="uniform"
                android:text="1" />
            <TextView
                android:layout_width="10dp"
                android:layout_height="match_parent"/>
            <Button
                android:id="@+id/num_2"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="match_parent"
                android:autoSizeTextType="uniform"
                android:text="2" />
            <TextView
                android:layout_width="10dp"
                android:layout_height="match_parent"/>
            <Button
                android:id="@+id/num_3"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="match_parent"
                android:autoSizeTextType="uniform"
                android:text="3" />
            <TextView
                android:layout_width="10dp"
                android:layout_height="match_parent"/>
            <Button
                android:id="@+id/btn_multiple"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="match_parent"
                android:autoSizeTextType="uniform"
                android:text="*" />
        </TableRow>
        
 
        <TableRow
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_weight="1">
            <Button
                android:id="@+id/btn_dot"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="match_parent"
                android:autoSizeTextType="uniform"
                android:text="." />
            <TextView
                android:layout_width="10dp"
                android:layout_height="match_parent"/>
            <Button
                android:id="@+id/num_0"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="match_parent"
                android:autoSizeTextType="uniform"
                android:text="0" />
            <TextView
                android:layout_width="10dp"
                android:layout_height="match_parent"/>
            <Button
                android:id="@+id/btn_result"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="match_parent"
                android:autoSizeTextType="uniform"
                android:text="=" />
            <TextView
                android:layout_width="10dp"
                android:layout_height="match_parent"/>
            <Button
                android:id="@+id/btn_slush"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="match_parent"
                android:autoSizeTextType="uniform"
                android:text="/" />
        </TableRow>
 
 
        <TableRow
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_weight="5"></TableRow>
 
    </TableLayout>
 
 
 
 
 
</TableLayout>

MainActivity.java

package com.example.calculator;
 
import androidx.appcompat.app.AppCompatActivity;
 
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
 
public class MainActivity extends AppCompatActivity {
    private static final String TAG = "Main_Activity";
 
    private TextView ptResult;
    private TextView ptResult2;
    private String s;
    private Button btn[] = new Button[20];
    private int i=0;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        init();
        initListener();
    }
 
    private void init(){
        btn[0]=findViewById(R.id.num_0);
        btn[1]=findViewById(R.id.num_1);
        btn[2]=findViewById(R.id.num_2);
        btn[3]=findViewById(R.id.num_3);
        btn[4]=findViewById(R.id.num_4);
        btn[5]=findViewById(R.id.num_5);
        btn[6]=findViewById(R.id.num_6);
        btn[7]=findViewById(R.id.num_7);
        btn[8]=findViewById(R.id.num_8);
        btn[9]=findViewById(R.id.num_9);
 
        btn[10]=findViewById(R.id.btn_plus);
        btn[11]=findViewById(R.id.btn_minus);
        btn[12]=findViewById(R.id.btn_multiple);
        btn[13]=findViewById(R.id.btn_slush);
        btn[14]=findViewById(R.id.btn_dot);
        btn[15]=findViewById(R.id.btn_per);
        btn[16]=findViewById(R.id.btn_left);
        btn[17]=findViewById(R.id.btn_right);
        btn[18]=findViewById(R.id.btn_clear);
        btn[19]=findViewById(R.id.btn_result);
        ptResult=findViewById(R.id.et_result);
        ptResult2=findViewById(R.id.et_result2);
    }
 
    private void initListener(){
        for (int i=1; i<10;i++){
            int I = i;
            btn[i].setOnClickListener((View view)-> {
                Button btn = (Button) view;
                ptResult.append(btn.getText().toString());
 
                String result3 = ptResult.getText().toString();
                double a = Double.valueOf(Eval.cal(result3));
                int b = (int) a;
 
                if(a == b) {
                    ptResult2.setText(Integer.toString(b));
                }
                else ptResult2.setText(Eval.cal(result3));
 
                s += btn.getText().toString();
            });
        }
 
        for (int i=10; i<16; i++) {
            btn[i].setOnClickListener((View view)-> {
                Button btn = (Button) view;
                ptResult.append(btn.getText().toString());
                s = "";
            });
        }
 
        btn[0].setOnClickListener((View view)-> {
            ptResult.append("0");
            ptResult2.append("0");
        });
        btn[16].setOnClickListener((View view) -> {
            ptResult.append("(");
            left_right();
        });
        btn[18].setOnClickListener((View view)-> {
            ptResult.setText("");
            ptResult2.setText("");
        });
 
        btn[19].setOnClickListener((View view)-> {
            String result2=ptResult.getText().toString();
            ptResult2.setText(Eval.cal(result2));
            ptResult.setText(Eval.cal(result2));
 
            String result3 = ptResult.getText().toString();
            double a = Double.valueOf(Eval.cal(result3));
            int b = (int) a;
 
            if(a == b) {
                ptResult.setText(Integer.toString(b));
                ptResult2.setText(Integer.toString(b));
            }
            else {
                ptResult.setText(Eval.cal(result3));
                ptResult2.setText(Eval.cal(result3));
            }
 
        });
    }
    private void left_right() {
        for (int i=1; i<10;i++){
            int I = i;
            btn[i].setOnClickListener((View view)-> {
                Button btn = (Button) view;
                ptResult.append(btn.getText().toString());
                s += btn.getText().toString();
            });
        }
 
        for (int i=10; i<16; i++) {
            btn[i].setOnClickListener((View view)-> {
                Button btn = (Button) view;
                ptResult.append(btn.getText().toString());
                s = "";
            });
        }
        btn[16].setOnClickListener((View view) -> {
            ptResult.append("(");
            left_right();
        });
        btn[17].setOnClickListener((View view) -> {
            ptResult.append(")");
            String result3 = ptResult.getText().toString();
            double a = Double.valueOf(Eval.cal(result3));
            int b = (int) a;
 
            if(a == b) {
                ptResult2.setText(Integer.toString(b));
            }
            else ptResult2.setText(Eval.cal(result3));
 
            initListener();
        });
        btn[0].setOnClickListener((View view)-> {
            ptResult.append("0");
            ptResult2.append("0");
        });
 
        btn[18].setOnClickListener((View view)-> {
            ptResult.setText("");
            ptResult2.setText("");
        });
    }
}

Eval.java

package com.example.calculator;
 
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
 
public class Eval {
    public static String cal(String result){
        ScriptEngineManager manager=new ScriptEngineManager();
        ScriptEngine engine=manager.getEngineByName("js");
        try{
            return engine.eval(result).toString();
        }catch (Exception e){
            e.printStackTrace();
        }
        return null;
    }
}

---

결과

정상적으로 작동하지만, 오류가 있다.

 

1. 괄호 연산이 오류가 있으면 앱이 닫힌다. 예를 들어서 ( 보다 ) 를 먼저 입력하면 앱이 닫힌다.

ex. 1+2+3) 입력시 앱이 닫힌다.

 

2. 연산자를 동시에 못 쓰도록 바꿔야한다.

ex. ++++ 입력 가능

---

수정할 부분

 

1. 주석처리를 너무 안 했다.

2. MainActivity.java 코드 중 불필요한 라인이 존재한다.

3. 위의 오류 사항을 수정해야한다.

4. 디자인 부분 개선

5. 지우기 기능 추가 (back space)

---

참고 블로그 itstudy-mary.tistory.com/179

안드로이드 스튜디오,java] 간단한 계산기 앱 만들기

 

위의 코드를 실행시키기 위해선 밑의 사이트에 접속 후

jar 파일 다운로드 -> library에 추가해야 Eval class가 정상적으로 작동할 수 있다.

ScriptEngine, ScriptEngineManager download www.java2s.com/Code/Jar/j/Downloadjsr223jar.htm

Download jsr223.jar : jsr223 « j « Jar File Download