java - 如何在一个有返回值的方法中进行网络操作,然后返回网络操作后的值?

Question

如何在一个有返回值的方法中进行网络操作,然后返回网络操作后的值?

比如

private String A(){

 StringRequest stringRequest=new StringRequest(Request.Method.POST, MyApplication.HOST + "/mobileLogin.do",
             new Response.Listener<String>() {
                        @Override
              public void onResponse(String s) {
sout("获取的"+s)
                           }
               }, new Response.ErrorListener() {
                   @Override
                   public void onErrorResponse(VolleyError volleyError) {

                   }
               }){
                   @Override
                   protected Map<String, String> getParams() throws AuthFailureError {
                       Map<String,String> map=new HashMap<>();
                       map.put("msgno","001010");
                       map.put("uid",s);
                       return super.getParams();
                   }
               };
               requestQueue.add(stringRequest);
   } 
   
   

我想返回这个获取的结果,但是volley的操作是在异步,根本没法return,那这个怎么办

Answer 1

You can use interface callback

1. Declare an interface first

public interface RequestCallback{
    void onSuccess(String data);
    void onFail(String error);
}

1. Then use

inside the method

private String A(RequestCallback callback){

 StringRequest stringRequest=new StringRequest(Request.Method.POST, MyApplication.HOST + "/mobileLogin.do",
             new Response.Listener<String>() {
                        @Override
              public void onResponse(String s) {
                    sout("获取的"+s)
                    if(callback!=null){
                      callback.onSuccess(s);
                    }
                    
                           }
               }, new Response.ErrorListener() {
                   @Override
                   public void onErrorResponse(VolleyError volleyError) {
                        if(callback!=null){
                            callback.onFail(volleyError.getMessage);
                        }
                        
                   }
               }){
                   @Override
                   protected Map<String, String> getParams() throws AuthFailureError {
                       Map<String,String> map=new HashMap<>();
                       map.put("msgno","001010");
                       map.put("uid",s);
                       return super.getParams();
                   }
               };
               requestQueue.add(stringRequest);
   } 

Answer 2

Use RxJava or EventBus

Answer 3

Then do it in the asynchronous callback function. Or pass in a method or function where the asynchronous return occurs.

Answer 4

You can change your mind and don’t need a volley中返回结果。当请求成功后对结果进行封装，例如直接使用List或者结合类进行存储，然后可以通过Handlermechanism to obtain data and operations from it.

Answer 5

I need a user information provider when using Rongyun. According to the stringId passed by his method, I then use this id to obtain the information corresponding to this id from my server,,, so there is no way to operate volley first,

RongIM.setUserInfoProvider(new RongIM.UserInfoProvider() {

        @Override
        public UserInfo getUserInfo(final String s) {

           volley操作,需要使用到s

Answer 6

You can use Handler directly
I re-read your question, it seems to involve multi-layer callbacks. I think RxAndroid is more suitable here

//假设已经有两个方法，getStringID()用于获取你的用户id
//getUserInfo(String s)根据传入的StringID从你的服务器上获取用户信息
//UserInfo是用户信息类

        Observable.create(new Observable.OnSubscribe<String>() {
            @Override
            public void call(Subscriber<? super String> subscriber) {
                subscriber.onNext(getStringID());//获取id
            }
        })
                .map(new Func1<String, String>() {
                    @Override
                    public String call(String s) {
                        //如果你要处理得到的StringID的话，写在这里，否则不用写
                        return s;
                    }
                })
                .flatMap(new Func1<String, Observable<UserInfo>>() {
                    @Override
                    public Observable<UserInfo> call(String s) {
                        //这个s就是上面return的
                        //返回一个包裹着UserInfo的Observable
                        return Observable.just(getUserInfo(s));
                    }
                })
                .subscribeOn(Schedulers.io())//这段代码上面的都会在子线程中工作
                .observeOn(AndroidSchedulers.mainThread())//这段代码下面的会在主线程中工作
                .subscribe(new Action1<UserInfo>() {
                    @Override
                    public void call(UserInfo userInfo) {
                        //你想对UserInfo进行的操作，比如显示个用户名啥的
                    }
                });

I have just started using it, and the code I write is not very pretty. . . Asking for guidance from experts