Android中兩個類讓你再也不用實現onActivityResult()

2019-10-21 21:42:05

字體：大中小

來源：轉載

供稿：網友

前言

當我們知道fragment僅僅可以收到自己請求的回調后，我們就可以用它來解耦activity中onActivityResult的邏輯了。一般情況下，如果一個activity中多個回調結果的話，onActivityResult()中會有各種case判斷，并且這種設計也打斷了流式寫法。那么我們索性建立一個無UI的fragment做精準的接收器，這樣就可以再也不寫onActivityResult()了。

Fragment：

/** * @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);  } }}

請求封裝類：

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); }}

發(fā)送請求和監(jiān)聽請求的代碼：

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(); }});

題外話：