Android Retrofit：其他类中需要的onNext值

Question

我将 Retrofit 与 Rx java 一起使用，并且我在 onNext 中获取身份验证令牌的值。根据 onNext 的结果，我必须通过在自定义标头中添加令牌来将数据发布到服务器。我应该将所有代码都写在 on next 中吗？有什么方法可以从 onNext 返回一个值，所以当值可用时？

public String getToken() {
    Retrofit retrofit = new Retrofit.Builder()
                        .baseUrl("https://abc.efg.com/")
                        .addConverterFactory(ScalarsConverterFactory.create())
                        .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
                        .build();
                GetTokenInterface service = retrofit.create(GetTokenInterface.class);

                Observable<String> response_call = service.getToken1(setAPI_KEY, setaccesstoken);

                response_call.subscribeOn(Schedulers.newThread())
                        .observeOn(AndroidSchedulers.mainThread())
                        .subscribe(new Subscriber<String>() {
                            @Override
                            public void onCompleted() {

                                System.out.print("Complete");
                            }

                            @Override
                            public void onError(Throwable e) {

                                System.out.print("Fail");
                            }

                            @Override
                            public void onNext(String token) {
                                authentication_token = token; //getting correct value here
                            }
                        });
                return authentication_token;
    }

}

然后在另一个班级：

generated_token = getToken();

但是由于值不可用，我得到了 generate_token null 有没有办法在其中获取值？我必须使用这个值来发布，还是需要在 onNext() 中合并 post observable？

Answer 1

RxJava 代码是异步执行的。例如

public class Foo {

    String value = "a";

    public String getFoo() {
        value = "a"; // This executes first
        Observable.just(value + "a")
                .observeOn(Schedulers.io())
                .subscribe(new Action1<String>() {
                    public void call(String v) {
                        value = v; // This is called later on IO thread.
                    }
                }); // This creates the observable and schedules execution on IO thread.
        return value; // Return value "a"
    }
}

Foo foo = new Foo();
foo.getFoo(); // Return a
Thread.sleep(100);
foo.getFoo(); // likley Return `aa` (depends upon how long the IO thread take to run)
Thread.sleep(100);
foo,getFoo(); // likley Return `aaa` (depends upon how long the IO thread take to run)

如果您想从您的方法 getToken 中获取一个值，您可以返回 Observable<String> 如果您愿意，您也可以将令牌保存在您的类中，如下所示。

public class TokenService {

    Retrofit retrofit = new Retrofit.Builder()
            .baseUrl("https://abc.efg.com/")
            .addConverterFactory(ScalarsConverterFactory.create())
            .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
            .build();
    GetTokenInterface service = retrofit.create(GetTokenInterface.class); // This should be done outside of the method for performance

    String savedToken;

    public Observable<String> refreshToken() {
        return service.getToken1(setAPI_KEY, setaccesstoken)
                .subscribeOn(Schedulers.newThread())
                .doOnNext(new Action1<String() {
                    public void call(String token) {
                        savedToken = token;
                    }
                }) // Do want is needed with token
                .observeOn(AndroidSchedulers.mainThread());
    }

    public String getSavedToken() {
        return savedToken;
    }

}