使用 Retrofit 和 RxJava 的 Http 请求答案

【问题标题】：Http request with Retrofit and RxJava使用 Retrofit 和 RxJava 的 Http 请求
【发布时间】：2016-07-20 08:42:02
【问题描述】：

我正在请求一个带有 Retrofit 2 库的 Web 服务 API。我有以下 API 的 URL 代码：

String ENDPOINT = "https://api.trakt.tv/";

@GET("movies/popular?limit=10&extended=full,images")
public Observable<PopularMoviesResponse> getPopularMovies(@Header("trakt-api-version") String trakt_api_version,
                                                  @Header("trakt-api-key") String trakt_api_key,
                                                  @Query("page") String page);

我在：

public Observable<List<PopularMovies>> fetchPopularMovies(String trakt_api_version,
                                                          String trakt_api_key,
                                                          String page) {
    return movieService
            .getPopularMovies(trakt_api_version, trakt_api_key, page)
            .concatMap(new Func1<PopularMoviesResponse, Observable<? extends List<PopularMovies>>>() {
                @Override
                public Observable<? extends List<PopularMovies>> call(final PopularMoviesResponse popularMoviesResponse) {
                    Log.d("uuuuuu", "oooooo");
                    return Observable.create(new Observable.OnSubscribe<List<PopularMovies>>() {
                        @Override
                        public void call(Subscriber<? super List<PopularMovies>> subscriber) {
                            Log.d("uuuuuu", "oooooo");
                            try {
                                if (subscriber.isUnsubscribed()) return;
                                subscriber.onNext(popularMoviesResponse.getPopularMovies());
                                subscriber.onCompleted();
                            } catch (Exception e) {
                                subscriber.onError(e);
                            }
                        }
                    });

                }
            });
}

日志数据告诉http状态码是200，okhttp正常记录响应。但是，在第二个 sn-p 代码中，没有到达日志！有什么问题？

更新，

这是订阅 observable 的代码：

public void getPopularMovies(final String page) {
    mDataManager.fetchPopularMovies(TraktAPI.TRAKT_API_VERSION.getValue(), TraktAPI.TRAKT_API_KEY.getValue(), page)
            .observeOn(AndroidSchedulers.mainThread())
            .subscribeOn(Schedulers.io())
            .subscribe(new Observer<List<PopularMovies>>() {
                @Override
                public void onCompleted() {
                }

                @Override
                public void onError(Throwable e) {
                    mMvpView.showEmpty();
                }

                @Override
                public void onNext(List<PopularMovies> popularMoviesList) {
                    Log.d("onNext", "pppppppppppp");
                    mMvpView.showListOfPopularMovies(popularMoviesList);
                }
            });
}

我在订阅代码中记录了 onError，我得到了以下堆栈跟踪：

07-20 12:15:16.547 2056-2056/org.unrwa.edits W/System.err: com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 2 path $
07-20 12:15:16.548 2056-2056/org.unrwa.edits W/System.err:     at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:221)
07-20 12:15:16.549 2056-2056/org.unrwa.edits W/System.err:     at com.google.gson.TypeAdapter.fromJson(TypeAdapter.java:260)
07-20 12:15:16.549 2056-2056/org.unrwa.edits W/System.err:     at retrofit2.GsonResponseBodyConverter.convert(GsonResponseBodyConverter.java:33)
07-20 12:15:16.549 2056-2056/org.unrwa.edits W/System.err:     at retrofit2.GsonResponseBodyConverter.convert(GsonResponseBodyConverter.java:23)
07-20 12:15:16.550 2056-2056/org.unrwa.edits W/System.err:     at retrofit2.OkHttpCall.parseResponse(OkHttpCall.java:154)
07-20 12:15:16.550 2056-2056/org.unrwa.edits W/System.err:     at retrofit2.OkHttpCall.execute(OkHttpCall.java:118)
07-20 12:15:16.550 2056-2056/org.unrwa.edits W/System.err:     at retrofit2.RxJavaCallAdapterFactory$CallOnSubscribe.call(RxJavaCallAdapterFactory.java:107)
07-20 12:15:16.551 2056-2056/org.unrwa.edits W/System.err:     at retrofit2.RxJavaCallAdapterFactory$CallOnSubscribe.call(RxJavaCallAdapterFactory.java:88)
07-20 12:15:16.551 2056-2056/org.unrwa.edits W/System.err:     at rx.Observable$2.call(Observable.java:162)
07-20 12:15:16.552 2056-2056/org.unrwa.edits W/System.err:     at rx.Observable$2.call(Observable.java:154)
07-20 12:15:16.552 2056-2056/org.unrwa.edits W/System.err:     at rx.Observable$2.call(Observable.java:162)
07-20 12:15:16.552 2056-2056/org.unrwa.edits W/System.err:     at rx.Observable$2.call(Observable.java:154)
07-20 12:15:16.553 2056-2056/org.unrwa.edits W/System.err:     at rx.Observable$2.call(Observable.java:162)
07-20 12:15:16.553 2056-2056/org.unrwa.edits W/System.err:     at rx.Observable$2.call(Observable.java:154)
07-20 12:15:16.553 2056-2056/org.unrwa.edits W/System.err:     at rx.Observable$2.call(Observable.java:162)
07-20 12:15:16.554 2056-2056/org.unrwa.edits W/System.err:     at rx.Observable$2.call(Observable.java:154)
07-20 12:15:16.555 2056-2056/org.unrwa.edits W/System.err:     at rx.Observable$2.call(Observable.java:162)
07-20 12:15:16.555 2056-2056/org.unrwa.edits W/System.err:     at rx.Observable$2.call(Observable.java:154)
07-20 12:15:16.556 2056-2056/org.unrwa.edits W/System.err:     at rx.Observable.unsafeSubscribe(Observable.java:8098)
07-20 12:15:16.556 2056-2056/org.unrwa.edits W/System.err:     at rx.internal.operators.OperatorSubscribeOn$1$1.call(OperatorSubscribeOn.java:62)
07-20 12:15:16.556 2056-2056/org.unrwa.edits W/System.err:     at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:55)
07-20 12:15:16.557 2056-2056/org.unrwa.edits W/System.err:     at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:423)
07-20 12:15:16.557 2056-2056/org.unrwa.edits W/System.err:     at java.util.concurrent.FutureTask.run(FutureTask.java:237)
07-20 12:15:16.558 2056-2056/org.unrwa.edits W/System.err:     at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:269)
07-20 12:15:16.558 2056-2056/org.unrwa.edits W/System.err:     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
07-20 12:15:16.558 2056-2056/org.unrwa.edits W/System.err:     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
07-20 12:15:16.559 2056-2056/org.unrwa.edits W/System.err:     at java.lang.Thread.run(Thread.java:818)

Web 服务 API 的 URL，可以使用以下链接找到： https://api.trakt.tv/movies/popular?(page=%271%27)&limit=10&extended=full,images

PopularMoviesResponse POJO 类

公共类 PopularMoviesResponse {

private String OdataContext;
private List<PopularMovies> popularMovies = new ArrayList<PopularMovies>();


/**
 * 
 * @param OdataContext
 *     The @odata.context
 */
public void setOdataContext(String OdataContext) {
    this.OdataContext = OdataContext;
}

/**
 * 
 * @return
 *     The value
 */
public List<PopularMovies> getPopularMovies() {
    return popularMovies;
}

/**
 *
 * @param popularMovies
 */
public void setPopularMovies(List<PopularMovies> popularMovies) {
    this.popularMovies = popularMovies;
}

}

PopularMovies 类

@Generated("org.jsonschema2pojo") 公共类 PopularMovies {

@SerializedName("title")
@Expose
private String title;
@SerializedName("year")
@Expose
private long year;
@SerializedName("ids")
@Expose
private Ids ids;
@SerializedName("tagline")
@Expose
private String tagline;
@SerializedName("overview")
@Expose
private String overview;
@SerializedName("released")
@Expose
private String released;
@SerializedName("runtime")
@Expose
private long runtime;
@SerializedName("trailer")
@Expose
private String trailer;
@SerializedName("homepage")
@Expose
private String homepage;
@SerializedName("rating")
@Expose
private double rating;
@SerializedName("votes")
@Expose
private long votes;
@SerializedName("updated_at")
@Expose
private String updatedAt;
@SerializedName("language")
@Expose
private String language;
@SerializedName("available_translations")
@Expose
private List<String> availableTranslations = new ArrayList<String>();
@SerializedName("genres")
@Expose
private List<String> genres = new ArrayList<String>();
@SerializedName("certification")
@Expose
private String certification;
@SerializedName("images")
@Expose
private Images images;

/**
 * No args constructor for use in serialization
 * 
 */
public PopularMovies() {
}

/**
 * 
 * @param trailer
 * @param genres
 * @param availableTranslations
 * @param ids
 * @param votes
 * @param runtime
 * @param homepage
 * @param released
 * @param updatedAt
 * @param certification
 * @param title
 * @param overview
 * @param images
 * @param year
 * @param language
 * @param rating
 * @param tagline
 */
public PopularMovies(String title, long year, Ids ids, String tagline, String overview, String released, long runtime, String trailer, String homepage, double rating, long votes, String updatedAt, String language, List<String> availableTranslations, List<String> genres, String certification, Images images) {
    this.title = title;
    this.year = year;
    this.ids = ids;
    this.tagline = tagline;
    this.overview = overview;
    this.released = released;
    this.runtime = runtime;
    this.trailer = trailer;
    this.homepage = homepage;
    this.rating = rating;
    this.votes = votes;
    this.updatedAt = updatedAt;
    this.language = language;
    this.availableTranslations = availableTranslations;
    this.genres = genres;
    this.certification = certification;
    this.images = images;
}

/**
 * 
 * @return
 *     The title
 */
public String getTitle() {
    return title;
}

/**
 * 
 * @param title
 *     The title
 */
public void setTitle(String title) {
    this.title = title;
}

public PopularMovies withTitle(String title) {
    this.title = title;
    return this;
}

/**
 * 
 * @return
 *     The year
 */
public long getYear() {
    return year;
}

/**
 * 
 * @param year
 *     The year
 */
public void setYear(long year) {
    this.year = year;
}

public PopularMovies withYear(long year) {
    this.year = year;
    return this;
}

/**
 * 
 * @return
 *     The ids
 */
public Ids getIds() {
    return ids;
}

/**
 * 
 * @param ids
 *     The ids
 */
public void setIds(Ids ids) {
    this.ids = ids;
}

public PopularMovies withIds(Ids ids) {
    this.ids = ids;
    return this;
}

/**
 * 
 * @return
 *     The tagline
 */
public String getTagline() {
    return tagline;
}

/**
 * 
 * @param tagline
 *     The tagline
 */
public void setTagline(String tagline) {
    this.tagline = tagline;
}

public PopularMovies withTagline(String tagline) {
    this.tagline = tagline;
    return this;
}

/**
 * 
 * @return
 *     The overview
 */
public String getOverview() {
    return overview;
}

/**
 * 
 * @param overview
 *     The overview
 */
public void setOverview(String overview) {
    this.overview = overview;
}

public PopularMovies withOverview(String overview) {
    this.overview = overview;
    return this;
}

/**
 * 
 * @return
 *     The released
 */
public String getReleased() {
    return released;
}

/**
 * 
 * @param released
 *     The released
 */
public void setReleased(String released) {
    this.released = released;
}

public PopularMovies withReleased(String released) {
    this.released = released;
    return this;
}

/**
 * 
 * @return
 *     The runtime
 */
public long getRuntime() {
    return runtime;
}

/**
 * 
 * @param runtime
 *     The runtime
 */
public void setRuntime(long runtime) {
    this.runtime = runtime;
}

public PopularMovies withRuntime(long runtime) {
    this.runtime = runtime;
    return this;
}

/**
 * 
 * @return
 *     The trailer
 */
public String getTrailer() {
    return trailer;
}

/**
 * 
 * @param trailer
 *     The trailer
 */
public void setTrailer(String trailer) {
    this.trailer = trailer;
}

public PopularMovies withTrailer(String trailer) {
    this.trailer = trailer;
    return this;
}

/**
 * 
 * @return
 *     The homepage
 */
public String getHomepage() {
    return homepage;
}

/**
 * 
 * @param homepage
 *     The homepage
 */
public void setHomepage(String homepage) {
    this.homepage = homepage;
}

public PopularMovies withHomepage(String homepage) {
    this.homepage = homepage;
    return this;
}

/**
 * 
 * @return
 *     The rating
 */
public double getRating() {
    return rating;
}

/**
 * 
 * @param rating
 *     The rating
 */
public void setRating(double rating) {
    this.rating = rating;
}

public PopularMovies withRating(double rating) {
    this.rating = rating;
    return this;
}

/**
 * 
 * @return
 *     The votes
 */
public long getVotes() {
    return votes;
}

/**
 * 
 * @param votes
 *     The votes
 */
public void setVotes(long votes) {
    this.votes = votes;
}

public PopularMovies withVotes(long votes) {
    this.votes = votes;
    return this;
}

/**
 * 
 * @return
 *     The updatedAt
 */
public String getUpdatedAt() {
    return updatedAt;
}

/**
 * 
 * @param updatedAt
 *     The updated_at
 */
public void setUpdatedAt(String updatedAt) {
    this.updatedAt = updatedAt;
}

public PopularMovies withUpdatedAt(String updatedAt) {
    this.updatedAt = updatedAt;
    return this;
}

/**
 * 
 * @return
 *     The language
 */
public String getLanguage() {
    return language;
}

/**
 * 
 * @param language
 *     The language
 */
public void setLanguage(String language) {
    this.language = language;
}

public PopularMovies withLanguage(String language) {
    this.language = language;
    return this;
}

/**
 * 
 * @return
 *     The availableTranslations
 */
public List<String> getAvailableTranslations() {
    return availableTranslations;
}

/**
 * 
 * @param availableTranslations
 *     The available_translations
 */
public void setAvailableTranslations(List<String> availableTranslations) {
    this.availableTranslations = availableTranslations;
}

public PopularMovies withAvailableTranslations(List<String> availableTranslations) {
    this.availableTranslations = availableTranslations;
    return this;
}

/**
 * 
 * @return
 *     The genres
 */
public List<String> getGenres() {
    return genres;
}

/**
 * 
 * @param genres
 *     The genres
 */
public void setGenres(List<String> genres) {
    this.genres = genres;
}

public PopularMovies withGenres(List<String> genres) {
    this.genres = genres;
    return this;
}

/**
 * 
 * @return
 *     The certification
 */
public String getCertification() {
    return certification;
}

/**
 * 
 * @param certification
 *     The certification
 */
public void setCertification(String certification) {
    this.certification = certification;
}

public PopularMovies withCertification(String certification) {
    this.certification = certification;
    return this;
}

/**
 * 
 * @return
 *     The images
 */
public Images getImages() {
    return images;
}

/**
 * 
 * @param images
 *     The images
 */
public void setImages(Images images) {
    this.images = images;
}

public PopularMovies withImages(Images images) {
    this.images = images;
    return this;
}

}

JSON 响应

[ { "title": "黑暗骑士", "year": 2008, "ids": { "trakt": 120, “蛞蝓”：“黑暗骑士 2008”，“imdb”：“tt0468569”，“tmdb”：155 }， “标语”：“为什么这么严肃？”，“概述”：“蝙蝠侠提高了赌注他对犯罪的战争。在 Lt. Jim Gordon 和地区的帮助下哈维·登特律师，蝙蝠侠着手拆除剩下的困扰街头的犯罪组织。伙伴关系证明是有效的，但他们很快发现自己成为了统治的牺牲品被恐惧者所熟知的犯罪主谋所引发的混乱作为小丑的哥谭市民。", "发布": "2008-07-18", “运行时”：152，“预告片”：“http://youtube.com/watch?v=GVx5K8WfFJY”， “主页”：“http://thedarkknight.warnerbros.com/dvdsite/”，“评分”： 9.03781，“投票”：24887，“updated_at”：“2016-07-13T10:06:28.000Z”，“语言”：“en”，“available_translations”：[“en”，“de”，“fi”， "sv", “zh”、“ru”、“nl”、“it”、“fr”、“hu”、“da”、“es”、“tr”、“pt”、“cs”、 “pl”、“bg”、“he”、“sr”、“no”、“el”、“sk”、“ja”、“th”、“ko”、“uk”、 “fa”、“lv”、“ro”、“id”、“bs”、“ca”]、“流派”：[“动作”、“犯罪”、 “戏剧”，“惊悚片”]，“认证”：“PG-13”，“图像”：{“同人画”： { “满的”： "https://walter.trakt.us/images/movies/000/000/120/fanarts/original/f7884a908e.jpg", “中等的”： "https://walter.trakt.us/images/movies/000/000/120/fanarts/medium/f7884a908e.jpg", “拇指”： "https://walter.trakt.us/images/movies/000/000/120/fanarts/thumb/f7884a908e.jpg" }，“海报”：{“完整”： "https://walter.trakt.us/images/movies/000/000/120/posters/original/8369bf0d4a.jpg", “中等的”： "https://walter.trakt.us/images/movies/000/000/120/posters/medium/8369bf0d4a.jpg", “拇指”： “https://walter.trakt.us/images/movies/000/000/120/posters/thumb/8369bf0d4a.jpg” }，“标志”：{“完整”： “https://walter.trakt.us/images/movies/000/000/120/logos/original/3e39105d34.png” }, "clearart": { "full": “https://walter.trakt.us/images/movies/000/000/120/cleararts/original/295bcec2cd.png” }，“横幅”：{“完整”： “https://walter.trakt.us/images/movies/000/000/120/banners/original/7065417461.jpg” }，“拇指”：{“完整”： “https://walter.trakt.us/images/movies/000/000/120/thumbs/original/6363cb8aeb.jpg” } } },

...

]

【问题讨论】：

您确定您订阅了来自fetchPopularMovies 的Observable 回报吗？能否请您展示您的那部分代码？
@Divers 我刚刚用代码更新了我的帖子。
尝试在您的订阅中登录onError。有没有什么？还要检查是否调用了onCompleted。
@Divers 我更新了我的帖子。 JSON 异常。我有以下网址：api.trakt.tv/movies/…
不鼓励使用Observable.create。此外，您不需要 concatMap，只需映射：getPopularMovies(...).map(p -> p.getPopularMovies())。如果仍然无效，请联系我们。

标签： android rx-java rx-android

【解决方案1】：

请尝试更改

public Observable<PopularMoviesResponse> getPopularMovies

到

public Observable<List<PopularMovies>> getPopularMovies

Android 你的方法然后：

public Observable<List<PopularMovies>> fetchPopularMovies(String trakt_api_version,
                                                          String trakt_api_key,
                                                          String page) {
    return movieService 
            .getPopularMovies(trakt_api_version, trakt_api_key, page)
}

UPD

只是为了确保您的 POJO 匹配 JSON，您可以使用 that service。在那个gist 你可以查看完整的结果。

【讨论】：

和第二个sn-p的代码应该是什么？我可能会将其更改为 List ！并且所有 POJO 都是使用该网站生成的。谢谢
@Androider 看来您的 API 已经返回了热门电影列表，因此您无需对其应用任何更改。
@Androider 实际上我不明白您为什么将 availableTranslations 字段放在 POJO 中。 JSON 中没有该字段。只需仔细检查您在 POJO 中的字段是否与 JSON 匹配，或者您可以使用我的要点。
是的，它正在发送另一个参数进行翻译。我看到了你的要点。无论如何，问题出在数组/对象中。现在根据您要求的新修改。必须更改代码的第二个 sn-p。如何在 onNext() 中返回 List ？
@Androider 我已经在我的回答中发布了fetchPopularMovies 方法。明确一点，JSON 是已经的热门电影列表，你不需要修改它。