android - 양방향 intent, 사칙연산

파일명 :  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="fill_parent"
    android:layout_height="fill_parent"
    tools:context=".MainActivity"
    android:orientation="vertical">

    <EditText
        android:id="@+id/edtNum1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
    <EditText
        android:id="@+id/edtNum2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
    <Button
        android:id="@+id/btnNewActivity"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="계산하기"/>

    <RadioGroup
        android:id="@+id/rGroup"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <RadioButton
            android:id="@+id/rBtnSum"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="더하기" />
        <RadioButton
            android:id="@+id/rBtnMinus"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="빼기" />
        <RadioButton
            android:id="@+id/rBtnMul"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="곱하기" />
        <RadioButton
            android:id="@+id/rBtnDiv"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="나누기" />
    </RadioGroup>

</LinearLayout>

파일명 : activity_second.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <Button
        android:id="@+id/btnReturn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="돌아가기"/>

</LinearLayout>

파일명 : MainActivity.java

package com.example.it.myapplication8_7;

import android.content.Intent;
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.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

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

        Button btnNewActivity = (Button) findViewById(R.id.btnNewActivity);
        final RadioGroup rGroup = (RadioGroup) findViewById(R.id.rGroup);

        btnNewActivity.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                EditText edtNum1 = (EditText) findViewById(R.id.edtNum1);
                EditText edtNum2 = (EditText) findViewById(R.id.edtNum2);

                Intent intent = new Intent(getApplicationContext(), SecondActivity.class);

                switch (rGroup.getCheckedRadioButtonId())
                {
                    case R.id.rBtnSum:
                        intent.putExtra("Operator", "+");
                        break;
                    case R.id.rBtnMinus:
                        intent.putExtra("Operator", "-");
                        break;
                    case R.id.rBtnMul:
                        intent.putExtra("Operator", "*");
                        break;
                    case R.id.rBtnDiv:
                        intent.putExtra("Operator", "/");
                        break;
                }

                intent.putExtra("Num1", Integer.parseInt(edtNum1.getText().toString()));
                intent.putExtra("Num2", Integer.parseInt(edtNum2.getText().toString()));

                //startActivity();// 주고 끝낸다.
                //startActivityForResult(); //결과 응답을 기다린다(받을때까지)
                startActivityForResult(intent, 0);

                //1. request: 요청
                //2. response: 응답 == result:결과
            }
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (resultCode == RESULT_OK) {
            int calResult = data.getIntExtra("CalResult", 0);

            RadioGroup rGroup = (RadioGroup) findViewById(R.id.rGroup);

            String str = "";
            switch (rGroup.getCheckedRadioButtonId()) {
                case R.id.rBtnSum :
                    str = "더하기 결과";
                    break;
                case R.id.rBtnMinus :
                    str = "빼기 결과";
                    break;
                case R.id.rBtnMul :
                    str = "곱하기 결과";
                    break;
                case R.id.rBtnDiv :
                    str = "나누기 결과";
                    break;
            }

            Toast.makeText(getApplicationContext(), str + " : " + calResult, Toast.LENGTH_SHORT).show();

        }
    }

}

파일명 : SecondActivity.java

package com.example.it.myapplication8_7;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class SecondActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);
        setTitle("Second 액티비티");

        Intent inIntent = getIntent();
        String operator = inIntent.getStringExtra("Operator");

        final int num1 = inIntent.getIntExtra("Num1", 0);
        final int num2 = inIntent.getIntExtra("Num2", 0);

        int HapValue = 0;
        if(operator.equals("+")) {
            HapValue = num1 + num2;
        } else if(operator.equals("-")) {
            HapValue = num1 - num2;
        } else if(operator.equals("*")) {
            HapValue = num1 * num2;
        } else if(operator.equals("/")) {
            HapValue = num1 / num2;
        }

        Button btnReturn = (Button) findViewById(R.id.btnReturn);
        final int finalHapValue = HapValue;
        btnReturn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent outIntent = new Intent(getApplicationContext(), MainActivity.class);
                outIntent.putExtra("CalResult", finalHapValue);
                setResult(RESULT_OK, outIntent);
                finish();
            }
        });


    }
}

파일명 : AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.it.myapplication8_7">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".SecondActivity"></activity>
    </application>

</manifest>