[Android Studio] StartActivityForResult

Activity 시작. 결과를 위해서

activity로 넘어갔다가 다시 옴

 

Sub은 SubActivity를 파괴시키면서 MainActivity로 넘어갈 계획

 

코드

activity_sub.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    tools:context=".SubActivity">

    <EditText
        android:id="@+id/et_comeback"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:hint="Main으로 보낼 값 입력해주세요."/>

    <Button
        android:id="@+id/btn_close"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="종료"/>


</LinearLayout>

SubActivity.java

package com.example.comebackexample;

import androidx.appcompat.app.AppCompatActivity;

import android.annotation.SuppressLint;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class SubActivity extends AppCompatActivity {

    private EditText et_comeback;
    private Button btn_close;

    @SuppressLint("MissingInflatedId")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_sub);

        et_comeback = findViewById(R.id.et_comeback);
        btn_close = findViewById(R.id.btn_close);

        btn_close.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(); //보통 위젯의 소문자로 intent 이런 식으로 쓴다
                intent.putExtra("comeback", et_comeback.getText().toString()); // 입력 폼에 적은 값 담아주기
                setResult(RESULT_OK, intent); // 결과 값 설정
                finish(); // 현재 액티비티 종료
            }
        });

    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/tv_comback"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="30sp"
        android:text="값을 가져와주세요" />

    <Button
        android:id="@+id/btn_go"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="GO"/>

</LinearLayout>

MainActivity.java

package com.example.comebackexample;

import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;

import android.annotation.SuppressLint;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    private TextView tv_comback;
    private Button btn_go;

    private static final int REQUEST_CODE = 777; // 상수 값을 선언 * 상수 (항상 같은 수 + 변하지 않을 수)
    @SuppressLint("MissingInflatedId")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        tv_comback = findViewById(R.id.tv_comback);
        btn_go = findViewById(R.id.btn_go);

        btn_go.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(getApplicationContext(), SubActivity.class);
                startActivityForResult(intent,REQUEST_CODE);
            }
        });

    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if(resultCode == RESULT_OK){ //통신이 resultCode다 수신 성공하면 RESULT_OK
            Toast.makeText(getApplicationContext(), "수신 성공",Toast.LENGTH_SHORT).show();
        } else {
            Toast.makeText(getApplicationContext(), "수신 실패",Toast.LENGTH_SHORT).show();
        }

        if(requestCode == REQUEST_CODE){
            String resultTxt = data.getStringExtra("comeback"); //갖고 온 값을
            tv_comback.setText(resultTxt); //setText
        }

    }
}

 

Sub에서 putExtra 하면 Main에서 getStringExtra로 받음.