Intent 값전달 및 받기

* MainActivity.java

public class MainActivity extends AppCompatActivity {

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

        Button button = findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(getApplicationContext(), MenuActivity.class);
                startActivityForResult(intent, 101);
            }
        });
    }

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

        if (requestCode == 101) {
            if (data != null) {
                String name =data.getStringExtra("name");
                if (name != null) {
                    Toast.makeText(getApplicationContext(), "응답받은 데이터 : " + name, Toast.LENGTH_LONG).show();
                }
            }

        }
    }
}

* MenuActivity.java

public class MenuActivity extends AppCompatActivity {

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

        Button button2 = findViewById(R.id.button2);
        button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent();
                intent.putExtra("name", "mike");
                setResult(RESULT_OK, intent);

                finish();
            }
        });
    }
}