[안드로이드 스튜디오] 서브 액티비티로부터 문자열 반환받기

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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:id="@+id/main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    android:orientation="vertical"
    android:gravity="center">

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="문자열 반환 받기">
    </Button>
    <TextView
        android:id="@+id/text1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="반환된 문자열">
    </TextView>
</LinearLayout>

<?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">
    <EditText
        android:id="@+id/edittext1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
    </EditText>

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:layout_gravity="center">
        <Button
            android:id="@+id/bt_submit"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="입력 완료"></Button>
        <Button
            android:id="@+id/bt_cancle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="취소"></Button>
    </LinearLayout>
</LinearLayout>

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JAVA

package com.example.a06_exercise;

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

import androidx.activity.EdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;

public class MainActivity extends AppCompatActivity {
    TextView text1;
    Button button1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        EdgeToEdge.enable(this);
        setContentView(R.layout.activity_main);

        text1 = findViewById(R.id.text1);
        button1 = findViewById(R.id.button1);

        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this, SecondActivity.class);
                startActivityForResult(intent, 0);
            }
        });

    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (resultCode == RESULT_OK) {
            String str = data.getStringExtra("text");
            text1.setText(str);
        }
    }
}

package com.example.a06_exercise;

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

import androidx.activity.EdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;

public class SecondActivity extends AppCompatActivity {
    EditText editText1;
    Button bt_submit, bt_cancle;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);

        editText1 = findViewById(R.id.edittext1);
        bt_submit = findViewById(R.id.bt_submit);
        bt_cancle = findViewById(R.id.bt_cancle);

        bt_submit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(SecondActivity.this, MainActivity.class);
                intent.putExtra("text", editText1.getText().toString());
                setResult(RESULT_OK, intent);
                finish();
            }
        });

        bt_cancle.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                editText1.setText("");
            }
        });
    }
}

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