前言
当我们知道fragment仅仅可以收到自己请求的回调后，我们就可以用它来解耦activity中onActivityResult的逻辑了。一般情况下，如果一个activity中多个回调结果的话，onActivityResult()中会有各种case判断，并且这种设计也打断了流式写法。那么我们索性建立一个无UI的fragment做精准的接收器，这样就可以再也不写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); } }} 请求封装类：
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); }} 发送请求和监听请求的代码：
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(); }}); 题外话：
最新的support包已经解决了fragment嵌套时里层的fragment收不到结果的问题，请及时更新依赖。
总结
以上就是这篇文章的全部内容了，希望本文的内容对大家的学习或者工作具有一定的参考学习价值，如果有疑问大家可以留言交流，谢谢大家对VEVB武林网的支持。
注：相关教程知识阅读请移步到Android开发频道。
