Android中两个类让你再也不用实现onActivityResult()
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：
/**
*@authorKale
*@date2018/4/13
*/
publicclassOnActResultEventDispatcherFragmentextendsFragment{
publicstaticfinalStringTAG="on_act_result_event_dispatcher";
privateSparseArraymCallbacks=newSparseArray<>();
@Override
publicvoidonCreate(BundlesavedInstanceState){
super.onCreate(savedInstanceState);
setRetainInstance(true);
}
publicvoidstartForResult(Intentintent,ActResultRequest.Callbackcallback){
mCallbacks.put(callback.hashCode(),callback);
startActivityForResult(intent,callback.hashCode());
}
@Override
publicvoidonActivityResult(intrequestCode,intresultCode,Intentdata){
super.onActivityResult(requestCode,resultCode,data);
ActResultRequest.Callbackcallback=mCallbacks.get(requestCode);
mCallbacks.remove(requestCode);
if(callback!=null){
callback.onActivityResult(resultCode,data);
}
}
}
请求封装类：
publicclassActResultRequest{
privateOnActResultEventDispatcherFragmentfragment;
publicActResultRequest(Activityactivity){
fragment=getEventDispatchFragment(activity);
}
privateOnActResultEventDispatcherFragmentgetEventDispatchFragment(Activityactivity){
finalFragmentManagerfragmentManager=activity.getFragmentManager();
OnActResultEventDispatcherFragmentfragment=findEventDispatchFragment(fragmentManager);
if(fragment==null){
fragment=newOnActResultEventDispatcherFragment();
fragmentManager
.beginTransaction()
.add(fragment,OnActResultEventDispatcherFragment.TAG)
.commitAllowingStateLoss();
fragmentManager.executePendingTransactions();
}
returnfragment;
}
privateOnActResultEventDispatcherFragmentfindEventDispatchFragment(FragmentManagermanager){
return(OnActResultEventDispatcherFragment)manager.findFragmentByTag(OnActResultEventDispatcherFragment.TAG);
}
publicvoidstartForResult(Intentintent,Callbackcallback){
fragment.startForResult(intent,callback);
}
publicinterfaceCallback{
voidonActivityResult(intresultCode,Intentdata);
}
}
发送请求和监听请求的代码：
Intentintent=newIntent(this,SecondActivity.class);
request.startForResult(intent,newActResultRequest.Callback(){
@Override
publicvoidonActivityResult(intresultCode,Intentdata){
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
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