android - 使用 REST 从 firebase 检索信息并使用 Retrofit 和 RxJava 进行解析时出现问题

Question

好吧，我一直在努力使用 REST API 响应来处理 Firebase 响应。问题是我不想为 Firebase 使用 Android 的库，而是使用原始的 rest api。长话短说，Firebase 的响应是:

{
    "object1": {
        "param1": true,
        "param2": "05",
        "param3": "String",
    },
    "object2": {
        "param1": true,
        "param2": "09",
        "param3": "String",
    }
}

retrofit 界面:

public interface ApiCalls {
    @GET("/objects.json")
    Observable<List<MyObject>> getObjects();
}

Gson Builder、Retrofit Builder 和 RxJava:

    Gson gson = new GsonBuilder()
            .setLenient()
            .create();

    Retrofit retrofit = new Retrofit.Builder()
            .baseUrl("https://my-service.firebaseio.com")
            .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
            .addConverterFactory(GsonConverterFactory.create(gson))
            .client(okHttpClient)
            .build();

    ApiCalls api = retrofit.create(ApiCalls.class);

    rx.Observable<List<MyObject>> call2 = api.getObjects();
    call2.subscribeOn(Schedulers.newThread())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe(new Subscriber<List<MyObject>>() {
                @Override
                public void onCompleted() {
                    Log.d("onCompleted", "Its completed");
                }

                @Override
                public void onError(Throwable e) {
                    Log.d("onError", e.getMessage());
                }

                @Override
                public void onNext(List<MyObject> MyObjects) {
                    Log.d("onNext", "NextItem");
                }
            });

执行时出现错误:

java.lang.IllegalStateException: Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 2 path $

有没有办法使用 RxJava 来解决这个问题，以便迭代来自服务器的对象列表？因为现在我期待一个数组，但 firebase 的响应不是一个数组，有没有办法解决这个问题？

Answer 1

好吧，感谢这条评论，我可以解决这个问题:

@VeereshCharantimath that is indeed the cause of the error: the JSON from Firebase is a map (Map), not a list. Care to post an answer? – Frank van Puffelen

在我修改响应的预期值后它开始工作:

改造 Api 调用

public interface ApiCalls {
    @GET("/objects.json")
    Observable<HashMap<String, MyObject>> getObjects();
}

RxJava

rx.Observable<HashMap<String, MyObject>> call2 = api.getObjects();
call2.subscribeOn(Schedulers.newThread())
        .observeOn(AndroidSchedulers.mainThread())
        .subscribe(new Subscriber<HashMap<String, MyObject>>() {
            @Override
            public void onCompleted() {
                Log.d("onCompleted", "Its completed");
            }

            @Override
            public void onError(Throwable e) {
                Log.d("onError", e.getMessage());
            }

            @Override
            public void onNext(HashMap<String, MyObject> MyObjects) {
                Log.d("onNext", "NextItem");
            }
        });