时间：2021-01-11 11:01:22 | 栏目：Android代码 | 点击：次
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