[안드로이드] 4. EditText와 TextView를 이용해서 간단한 계산기 만들기.

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">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        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>

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

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

        </Button>

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

        </Button>

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

        </Button>

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

        </Button>

        <TextView
            android:id="@+id/TextResult"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="30dp"
            android:textColor="#FF0000"
            android:text="계산 결과 : "
            >
        </TextView>


    </LinearLayout>


</LinearLayout>

java

package com.example.homework2;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.MotionEvent;
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;
    TextView textResult;
    String num1, num2, tmp;
    Integer result;


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


        edit1 = (EditText)findViewById(R.id.Edit1);
        edit2 = (EditText)findViewById(R.id.Edit2);

        textResult = (TextView)findViewById(R.id.TextResult);

    }

    // 덧셈 method
    public void AddClick(View target)
    {
        num1 = edit1.getText().toString();
        num2 = edit2.getText().toString();

        if ((isInteger(num1) & isInteger(num2))==1)
        {
            result = Integer.parseInt(num1) + Integer.parseInt(num2);
            tmp = "계산 결과 : " + result.toString();
            textResult.setText(tmp);
        }
        else
        {
            Toast.makeText(getApplicationContext(), "No Number", Toast.LENGTH_LONG).show();
        }

    }

    // 뺄셈 method
    public void SubClick(View target)
    {
        num1 = edit1.getText().toString();
        num2 = edit2.getText().toString();

        if ((isInteger(num1) & isInteger(num2))==1)
        {
            result = Integer.parseInt(num1) - Integer.parseInt(num2);
            tmp = "계산 결과 : " + result.toString();
            textResult.setText(tmp);
        }
        else
        {
            Toast.makeText(getApplicationContext(), "No Number", Toast.LENGTH_LONG).show();
        }
    }

    // 곱셈 method
    public void MultiClick(View target)
    {
        num1 = edit1.getText().toString();
        num2 = edit2.getText().toString();

        if ((isInteger(num1) & isInteger(num2))==1)
        {
            result = Integer.parseInt(num1) * Integer.parseInt(num2);
            tmp = "계산 결과 : " + result.toString();
            textResult.setText(tmp);
        }
        else
        {
            Toast.makeText(getApplicationContext(), "No Number", Toast.LENGTH_LONG).show();
        }
    }

    // 나눗셈 method
    public void DivClick(View target)
    {
        num1 = edit1.getText().toString();
        num2 = edit2.getText().toString();

        if ((isInteger(num1) & isInteger(num2))==1)
        {
            result = Integer.parseInt(num1) / Integer.parseInt(num2);
            tmp = "계산 결과 : " + result.toString();
            textResult.setText(tmp);
        }
        else
        {
            Toast.makeText(getApplicationContext(), "No Number", Toast.LENGTH_LONG).show();
        }
    }

    // integer type method
    static int isInteger(String s) {
        try {
            Integer.parseInt(s);
            return 1;
        } catch(NumberFormatException e) {
            return 0;
        }
    }

}

 

 

 

 

EditText

// EditText
EditText edit = (EditText)findViewById(R.id.Edit);

// return string 
edit.getText().toString();

 

 

TextView

// TextView
text = (TextView)findViewById(R.id.Text);

text.setText(edittext.getText());

 

 

developer.android.com/reference/android/widget/EditText

EditText  |  Android 개발자  |  Android Developers

developer.android.com/reference/android/widget/TextView

TextView  |  Android 개발자  |  Android Developers