Android 계산기

[ 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"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.mijinpark.calculator.MainActivity">
 
    <!-- 창 -->
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="2"
        android:orientation="vertical">
 
        <TextView
            android:id="@+id/view"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"/>
 
        <TextView
            android:id="@+id/invisivleView"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:text="0"/>
    </LinearLayout>
 
    <!-- 버튼 -->
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="5"
        android:orientation="horizontal">
 
        <!-- 숫자부분 -->
        <LinearLayout
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="3"
            android:orientation="vertical">
 
            <!-- 첫째줄 -->
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:layout_weight="1">
 
                    <Button
                        android:id="@+id/back"
                        android:layout_width="0dp"
                        android:layout_height="match_parent"
                        android:layout_weight="1"
                        android:text="←"/>
                    <Button
                        android:id="@+id/CE"
                        android:layout_width="0dp"
                        android:layout_height="match_parent"
                        android:layout_weight="1"
                        android:text="CE"/>
                    <Button
                        android:id="@+id/C"
                        android:layout_width="0dp"
                        android:layout_height="match_parent"
                        android:layout_weight="1"
                        android:text="C"/>
            </LinearLayout>
 
            <!-- 둘째줄 -->
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:layout_weight="1">
 
                <Button
                    android:id="@+id/seven"
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:text="7"/>
                <Button
                    android:id="@+id/eight"
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:text="8"/>
                <Button
                    android:id="@+id/nine"
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:text="9"/>
            </LinearLayout>
 
            <!-- 셋째줄 -->
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:layout_weight="1">
 
                <Button
                    android:id="@+id/four"
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:text="4"/>
                <Button
                    android:id="@+id/five"
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:text="5"/>
                <Button
                    android:id="@+id/six"
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:text="6"/>
            </LinearLayout>
 
            <!-- 넷째줄 -->
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:layout_weight="1">
 
                <Button
                    android:id="@+id/one"
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:text="1"/>
                <Button
                    android:id="@+id/two"
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:text="2"/>
                <Button
                    android:id="@+id/three"
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:text="3"/>
            </LinearLayout>
 
            <!-- 다섯째줄 -->
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:layout_weight="1">
 
                <Button
                    android:id="@+id/zero"
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="2"
                    android:text="0"/>
 
                <Button
                    android:id="@+id/point"
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:text="."/>
            </LinearLayout>
        </LinearLayout>
 
        <!-- 연산부분 -->
        <LinearLayout
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="2"
            android:orientation="vertical">
 
            <!-- 첫째줄 -->
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="0dp"
                android:layout_weight="1">
                
                <Button
                    android:id="@+id/reverse"
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:text="±"/>
                <Button
                    android:id="@+id/root"
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:text="√"/>
            </LinearLayout>
 
            <!-- 둘째줄 -->
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="0dp"
                android:layout_weight="1">
 
                <Button
                    android:id="@+id/div"
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:text="/"/>
                <Button
                    android:id="@+id/per"
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:text="%"/>
            </LinearLayout>
 
            <!-- 셋째줄 -->
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="0dp"
                android:layout_weight="1">
 
                <Button
                    android:id="@+id/mul"
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:text="*"/>
                <Button
                    android:id="@+id/reciprocal"
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:text="1/x"/>
            </LinearLayout>
 
            <!-- 넷째줄 -->
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="0dp"
                android:layout_weight="2"
                android:orientation="horizontal">
 
                <LinearLayout
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:orientation="vertical">
 
                    <Button
                        android:id="@+id/minus"
                        android:layout_width="match_parent"
                        android:layout_height="0dp"
                        android:layout_weight="1"
                        android:text="-"/>
 
                    <Button
                        android:id="@+id/plus"
                        android:layout_width="match_parent"
                        android:layout_height="0dp"
                        android:layout_weight="1"
                        android:text="+"/>
 
                </LinearLayout>
 
                <LinearLayout
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1">
 
                    <Button
                        android:id="@+id/equal"
                        android:layout_width="0dp"
                        android:layout_height="match_parent"
                        android:layout_weight="1"
                        android:text="="/>
 
                </LinearLayout>
 
            </LinearLayout>
        </LinearLayout>
 
    </LinearLayout>
 
 
</LinearLayout>

 

 

 

[ Calculator.java ]

package com.example.mijinpark.calculator;
 
/**
 * Created by MiJin Park on 2016-05-28.
 */
public class Calculator {
    double number1;
    double number2;
    String op;
    double tempResult;
 
    public Calculator(){
        //의미없는 숫자로 초기화
        number1 = -0.023478;
        number2 = -0.023478;
        op = "";
    }
 
    public void setNumber1(double number1){
        this.number1 = number1;
    }
    public double getNumber1(){
        return number1;
    }
    public void setNumber2(double number2){
        this.number2 = number2;
    }
    public double getNumber2(){
        return number2;
    }
    public void setOp(String op){
        this.op = op;
    }
    public String getOp(){
        return op;
    }
 
    // 계산
    public double calc() {
 
        try {
            if (op.equals("+")) {
                tempResult = number1 + number2;
            } else if (op.equals("-")) {
                tempResult = number1 - number2;
            } else if (op.equals("*")) {
                tempResult = number1 * number2;
            } else if (op.equals("/")) {
                try {
                    tempResult = number1 / number2;
                } catch (ArithmeticException e) {
                    e.printStackTrace();
                }
            }else{
                tempResult = 0;
            }
            return tempResult;
        }catch (Exception e) {
            e.printStackTrace();
        }
        return tempResult;
    }
}

 

 

 

[ MainActivity.java ]

package com.example.mijinpark.calculator;
 
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
 
public class MainActivity extends AppCompatActivity {
 
    TextView view;
    TextView viewInvisible;
 
    Button btnBack;
    Button btnCE;
    Button btnC;
    Button btnRev;
    Button btnRoot;
    Button btnDiv;
    Button btnPer;
    Button btnMul;
    Button btnRec;
    Button btnMinus;
    Button btnPlus;
    Button btnEqu;
    Button btnPoint;
 
    Button btn0;
    Button btn1;
    Button btn2;
    Button btn3;
    Button btn4;
    Button btn5;
    Button btn6;
    Button btn7;
    Button btn8;
    Button btn9;
 
    Calculator cal = new Calculator();
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        view = (TextView) findViewById(R.id.view);
        viewInvisible = (TextView) findViewById(R.id.invisivleView);
 
        btnBack = (Button) findViewById(R.id.back);
        btnCE = (Button) findViewById(R.id.CE);
        btnC = (Button) findViewById(R.id.C);
        btnRev = (Button) findViewById(R.id.reverse);
        btnRoot = (Button) findViewById(R.id.root);
        btnDiv = (Button) findViewById(R.id.div);
        btnPer = (Button) findViewById(R.id.per);
        btnMul = (Button) findViewById(R.id.mul);
        btnRec = (Button) findViewById(R.id.reciprocal);
        btnMinus = (Button) findViewById(R.id.minus);
        btnPlus = (Button) findViewById(R.id.plus);
        btnEqu = (Button) findViewById(R.id.equal);
        btnPoint = (Button) findViewById(R.id.point);
 
        btn0 = (Button) findViewById(R.id.zero);
        btn1 = (Button) findViewById(R.id.one);
        btn2 = (Button) findViewById(R.id.two);
        btn3 = (Button) findViewById(R.id.three);
        btn4 = (Button) findViewById(R.id.four);
        btn5 = (Button) findViewById(R.id.five);
        btn6 = (Button) findViewById(R.id.six);
        btn7 = (Button) findViewById(R.id.seven);
        btn8 = (Button) findViewById(R.id.eight);
        btn9 = (Button) findViewById(R.id.nine);
 
 
        /**************숫자 키**************/
        btn0.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){
                setNumber("0");}
        });
        btn1.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){
                setNumber("1");}
        });
        btn2.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){
                setNumber("2");}
        });
        btn3.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){
                setNumber("3");}
        });
        btn4.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){
                setNumber("4");}
        });
        btn5.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){
                setNumber("5");}
        });
        btn6.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){
                setNumber("6");}
        });
        btn7.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){
                setNumber("7");}
        });
        btn8.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){
                setNumber("8");}
        });
        btn9.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){
                setNumber("9");}
        });
        btnPoint.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                viewInvisible.setText(viewInvisible.getText().toString() + ".");
            }
        });
 
 
        /**************사칙연산 키**************/
        btnMinus.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                view.setText(view.getText()+viewInvisible.getText().toString()+"-");
                setCal("-");
            }
        });
        btnPlus.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                view.setText(view.getText()+viewInvisible.getText().toString()+"+");
                setCal("+");
            }
        });
        btnDiv.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                view.setText(view.getText()+viewInvisible.getText().toString()+"/");
                setCal("/");
            }
        });
        btnMul.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                view.setText(view.getText()+viewInvisible.getText().toString()+"*");
                setCal("*");
            }
        });
 
        /**************±,= 연산 키**************/
        btnRev.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){
                viewInvisible.setText(((-1)*Double.parseDouble(viewInvisible.getText().toString()))+"");
            }
        });
 
        btnEqu.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){
                cal.setNumber2(Double.parseDouble(viewInvisible.getText().toString()));
                view.setText("");
                viewInvisible.setText(cal.calc()+"");
                cal.setNumber1(-0.023478);
                cal.setNumber2(-0.023478);
                cal.setOp("");
            }
        });
 
        /**************기능 키**************/
        btnBack.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){
                int len = viewInvisible.getText().length();
                if(len>0){
                    viewInvisible.setText(viewInvisible.getText().toString().substring(0,len-1));
                }
            }
        });
        //C는 완전히 초기화시키는 버튼
        btnC.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){
                view.setText("");
                viewInvisible.setText("0");
                cal.setNumber1(-0.023478);
                cal.setNumber2(-0.023478);
                cal.setOp("");
            }
        });
        //CE는 현재 쓰고있는 값 (viewInvisible에 있는 값)만 초기화하는 버튼
        btnCE.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){
                //view에 값이 없으면 완전 초기화
                if(view.getText().toString().equals("")){
                    cal.setNumber1(-0.023478);
                    cal.setNumber2(-0.023478);
                    cal.setOp("");
                }
                viewInvisible.setText("0");
            }
        });
 
    }
 
 
 
    // 숫자 입력 function
    public void setNumber(String i){
 
        if(viewInvisible.getText().equals("0")){
            viewInvisible.setText(i);
        }else {
            viewInvisible.setText(viewInvisible.getText().toString() + i);
        }
    }
 
    // 계산 function
    public void setCal(String op){
 
        if(viewInvisible.getText().equals("")){
            int len = view.getText().length();
            try{
                if(len>0){
                    view.setText((view.getText().toString().substring(0,len-2))+op);
                }
            }catch (Exception e){
                view.setText(view.getText().toString().substring(0,0)+op);
            }
 
        }else{
            if (cal.getNumber1()==-0.023478){
                try{
                    cal.setNumber1(Double.parseDouble(viewInvisible.getText().toString()));
                }catch (Exception e){
                    cal.setNumber1(0);
                }
            }else if(cal.getNumber2()==-0.023478){
                try{
                    cal.setNumber2(Double.parseDouble(viewInvisible.getText().toString()));
                }catch (NumberFormatException e){
                    //여기에 항등원넣으면 됨
                    if(op.equals("+")||op.equals("-")){
                        cal.setNumber2(0);
                    }else if (op.equals("*")||op.equals("/")){
                        cal.setNumber2(1);
                    }
                }
                cal.setNumber1(cal.calc());
                cal.setNumber2(-0.023478);
            }
        }
        cal.setOp(op);
        viewInvisible.setText("");
 
    }
}