Android 액티비티 데이터 전달 예제 launcher (더하기)

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"
    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/btnAdd"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="더하기"/>


</LinearLayout>

 

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=".MainActivity_Sub"
    android:orientation="vertical">

    <Button
        android:id="@+id/btnBack"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="BACK(MainActivity_sub)" />


</LinearLayout>

---

main.activity

public class MainActivity extends AppCompatActivity {

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

        Button button = findViewById(R.id.btnAdd);
        EditText edtNum1 = findViewById(R.id.edtNum1);
        EditText edtNum2 = findViewById(R.id.edtNum2);

        ActivityResultLauncher<Intent> launcher = registerForActivityResult(
                new ActivityResultContracts.StartActivityForResult(),
                new ActivityResultCallback<ActivityResult>() {
                    @Override
                    public void onActivityResult(ActivityResult result) {
                        if (result.getResultCode() == Activity.RESULT_OK) {
                            //로그 찍기
                            Log.d("ActivityResult : ", result.toString());

                                Intent intent = result.getData();
                                int sum = intent.getIntExtra("sum",0    );
                            Toast.makeText(getApplicationContext(),"합계 : " + sum, Toast.LENGTH_SHORT).show();
                        }
                    }
                });

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(MainActivity.this, MainActivity_Sub.class);
                intent.putExtra("Num1",Integer.parseInt(edtNum1.getText().toString()));
                intent.putExtra("Num1",Integer.parseInt(edtNum2.getText().toString()));
                
                launcher.launch(intent);
            }
        });

        }
    }

sub.activity

public class MainActivity_Sub extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_sub);

        Intent intent = getIntent();
        int num1 = intent.getIntExtra("Num1",0);
        int num2 = intent.getIntExtra("Num2",0);
        int sum = num1 + num2;

        Button button = findViewById(R.id.btnBack);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent  intent1 =new Intent(getApplicationContext(),MainActivity.class);
                setResult(RESULT_OK, intent1);
                intent1.putExtra("sum",sum);
                finish();
            }
        });

    }
}

---

결과 값