Android用電卓アプリ

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    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=".MainActivity" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:gravity="center|right"
        android:text="@string/result"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:textSize="50sp" />

    <LinearLayout
        android:id="@+id/linearLayout2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/linearLayout1"
        android:layout_centerVertical="true"
        android:gravity="center" >

        <Button
            android:id="@+id/Button4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/button4" />

        <Button
            android:id="@+id/Button5"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/button5" />

        <Button
            android:id="@+id/Button6"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/button6" />

        <Button
            android:id="@+id/Times"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/times" />
    </LinearLayout>

    <LinearLayout
        android:id="@+id/linearLayout3"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/linearLayout2"
        android:layout_below="@+id/linearLayout2"
        android:layout_marginTop="19dp"
        android:gravity="center" >

        <Button
            android:id="@+id/Button1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/button1" />

        <Button
            android:id="@+id/Button2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/button2" />

        <Button
            android:id="@+id/Button3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/button3" />

        <Button
            android:id="@+id/Divide"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/divide" />
    </LinearLayout>

    <LinearLayout
        android:id="@+id/linearLayout4"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/linearLayout3"
        android:layout_below="@+id/linearLayout3"
        android:layout_marginTop="17dp"
        android:gravity="center" >

        <Button
            android:id="@+id/Button0"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/button0" />

        <Button
            android:id="@+id/Plus"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/plus" />

        <Button
            android:id="@+id/Minus"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/minus" />

        <Button
            android:id="@+id/Equal"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/equal" />
    </LinearLayout>

    <LinearLayout
        android:id="@+id/linearLayout1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_above="@+id/linearLayout2"
        android:layout_alignLeft="@+id/textView1"
        android:layout_marginBottom="15dp"
        android:gravity="center" >

        <Button
            android:id="@+id/Button7"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/button7" />

        <Button
            android:id="@+id/Button8"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/button8" />

        <Button
            android:id="@+id/Button9"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/button9" />

        <Button
            android:id="@+id/Clear"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/clear" />
    </LinearLayout>

</RelativeLayout>

MainActivity.java

package com.example.calculator;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends Activity implements OnClickListener {

	private int result = 0;
	private int before_operator = -1;
	private int value = 0;
	private boolean wait = false;
	
	private int[] Numbers = { R.id.Button0, R.id.Button1, R.id.Button2,
							R.id.Button3, R.id.Button4, R.id.Button5, R.id.Button6,
							R.id.Button7, R.id.Button8, R.id.Button9 };
	private int[] Operators = {R.id.Plus, R.id.Minus, R.id.Times, R.id.Divide};

	private void calculate(){
    	switch(before_operator){
    		case R.id.Plus:
    			result = value + result;
    			break;
    			
    		case R.id.Minus:
    			result = value - result;
    			break;
    			
    		case R.id.Times:
    			result = value * result;
    			break;
    			
    		case R.id.Divide:
    			result = value / result;
    			break;
		}
    	value = 0;
		before_operator = -1;
		wait = true;
    }
	
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        for(int i=0;i<10;i++){
        	Button button = (Button)findViewById(Numbers[i]);
        	button.setOnClickListener(this);
        }
        
        for(int i=0;i<4;i++){
        	Button button = (Button)findViewById(Operators[i]);
        	button.setOnClickListener(this);
        }
        
        Button clear = (Button)findViewById(R.id.Clear);
        clear.setOnClickListener(new View.OnClickListener(){
        	public void onClick(View v){
        		result = 0;
        		before_operator = -1;
        		value = 0;
        		show();
        	}
        });
        
        Button equal = (Button)findViewById(R.id.Equal);
        equal.setOnClickListener(new View.OnClickListener(){
        	public void onClick(View v){
        		calculate();
        		show();
        	}
        });
    }
    
    private void show(){
    	TextView textview = (TextView)findViewById(R.id.textView1);
    	textview.setText(Integer.toString(result));
    }
    
    @Override
	public void onClick(View v) {
		for(int i=0;i<10;i++){
			if(v.getId() == Numbers[i]){
				if(wait){
					wait = false;
					result = 0;
				}
				result = result*10 + i;
				show();
				return ;
			}
		}
		
		if(before_operator != -1){
			calculate();
			show();
		}
		before_operator = v.getId();
		value = result;
		wait = true;
	}
    

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    
}

strings.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string name="app_name">電卓</string>
    <string name="action_settings">Settings</string>
    <string name="result">0</string>
    <string name="plus">+</string>
    <string name="minus">－</string>
    <string name="times">×</string>
    <string name="divide">÷</string>
    <string name="button0">0</string>
    <string name="button1">1</string>
    <string name="button2">2</string>
    <string name="button3">3</string>
    <string name="button4">4</string>
    <string name="button5">5</string>
    <string name="button6">6</string>
    <string name="button7">7</string>
    <string name="button8">8</string>
    <string name="button9">9</string>
    <string name="equal">=</string>
    <string name="clear">C</string>

</resources>