Android中两个类让你再也不用实现onActivityResult()

/**
 * @author Kale
 * @date 2018/4/13
 */
public class OnActResultEventDispatcherFragment extends Fragment {

 public static final String TAG = "on_act_result_event_dispatcher";

 private SparseArray<ActResultRequest.Callback> mCallbacks = new SparseArray<>();

 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setRetainInstance(true);
 }

 public void startForResult(Intent intent, ActResultRequest.Callback callback) {
  mCallbacks.put(callback.hashCode(), callback);
  startActivityForResult(intent, callback.hashCode());
 }

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

  ActResultRequest.Callback callback = mCallbacks.get(requestCode);
  mCallbacks.remove(requestCode);

  if (callback != null) {
   callback.onActivityResult(resultCode, data);
  }
 }
}

public class ActResultRequest {

 private OnActResultEventDispatcherFragment fragment;

 public ActResultRequest(Activity activity) {
  fragment = getEventDispatchFragment(activity);
 }

 private OnActResultEventDispatcherFragment getEventDispatchFragment(Activity activity) {
  final FragmentManager fragmentManager = activity.getFragmentManager();

  OnActResultEventDispatcherFragment fragment = findEventDispatchFragment(fragmentManager);
  if (fragment == null) {
   fragment = new OnActResultEventDispatcherFragment();
   fragmentManager
     .beginTransaction()
     .add(fragment, OnActResultEventDispatcherFragment.TAG)
     .commitAllowingStateLoss();
   fragmentManager.executePendingTransactions();
  }
  return fragment;
 }

 private OnActResultEventDispatcherFragment findEventDispatchFragment(FragmentManager manager) {
  return (OnActResultEventDispatcherFragment) manager.findFragmentByTag(OnActResultEventDispatcherFragment.TAG);
 }

 public void startForResult(Intent intent, Callback callback) {
  fragment.startForResult(intent, callback);
 }

 public interface Callback {

  void onActivityResult(int resultCode, Intent data);
 }
}

Intent intent = new Intent(this, SecondActivity.class);

request.startForResult(intent, new ActResultRequest.Callback() {
 @Override
 public void onActivityResult(int resultCode, Intent data) {
  Toast.makeText(MainActivity.this, "" + resultCode, Toast.LENGTH_SHORT).show();
 }
});