onActivityResult()的两个实现类

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。

public class OnActResultEventDispatcherFragment extends Fragment { 
    public static final String TAG = "on_act_result_event_dispatcher"; 
    private SparseArray mCallbacks = new SparseArray<>(); 

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

    public void startForResult(Intent intent, ActResultRequest.Callback 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(); 
    } 
});

以上就是关于onActivityResult()的两个实现类。

作者：缪枢民

原文链接：点击这里

onActivityResult()的两个实现类

onActivityResult()的两个实现类

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