Android 8日目

ActivityResultLauncher<Intent> launcher = registerForActivityResult(
       new ActivityResultContracts.StartActivityForResult(),
       new ActivityResultCallback<ActivityResult>() {
           @Override
           public void onActivityResult(ActivityResult result) {
               if(result.getResultCode() == RESULT_OK){
                   Intent intent = result.getData();

                   
                   Log.d("FirstActivity", intent.getStringExtra("msg"));
               }
           }
       }
);

     btn2.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent intent = new Intent(FirstActivity.this,ThirdActivity.class);

            launcher.launch(intent);
        }
    });

ThirdActivity

import androidx.appcompat.app.AppCompatActivity;

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

public class ThirdActivity extends AppCompatActivity {
    Button btn;
    EditText edt;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_third);

    edt = findViewById(R.id.edtMsg);
    btn = findViewById(R.id.btnThird);
    btn.setOnClickListener(new View.OnClickListener() {
       @Override
         public void onClick(View view) {
            String msg = edt.getText().toString();

            Intent intent = new Intent();
            intent.putExtra("msg",msg);
           setResult(RESULT_OK,intent);
           finish();
          }
        });
  }
}

実行画面

コンソール出力画面