public class MainActivity extends AppCompatActivity {

    private RxActivityLauncher launcher = new RxActivityLauncher();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // If the screen is rotated. Use RxBinding to trigger.
        // https://github.com/JakeWharton/RxBinding
        Observable<Void> trigger = RxView.clicks(findViewById(R.id.button))
        launcher.from(this)
                .on(trigger)
                .startActivityForResult(intent, REQUEST_ANY, null)
                .subscribe(result -> {
                    // If you specify a trigger, even if an exception occurs onError it is not called.
                    // So, the error handling in onNext.
                    if (result.throwable != null) {
                        // Error handling.
                        return;
                    }
                    // Do something.
                 }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        // Always you must call the following #onActivityResult.
        launcher.onActivityResult(requestCode, resultCode, data);
    }

    // In the case of explicit intent
    private void startActivityUsingExplicitIntent() {
      Intent intent = new Intent(this, AnyActivity.class);
      launcher.from(this)
               .startActivityForResult(intent, REQUEST_ANY, null)
               .subscribe(result -> {
                   if (result.isOk()) {
                       // Do in the case of RESULT_OK  
                   } else {
                       // Do in the case of RESULT_CANCELD etc.
                   }
               });
    }

    // In the case of implicit intent
    private void startActivityUsingImplicitIntent() {
      Intent intent = new Intent(ANY_ACTION);
      launcher.from(this)
               .startActivityForResult(intent, REQUEST_ANY, null)
               .subscribe(new Action1<ActivityResult>() {
                   @Override
                   public void call(ActivityResult result) {
                       // Do in the case of received any result.
                   }
               }, new Action1<Throwable>() {
                   @Override
                   public void call(Throwable throwable) {
                       // Exception might occur in implicit Intent.
                   }
               });
    }
}