一个学习Android的iOS开发人员提出的两部分问题,他正在开发一个Android项目,该项目将提出从JSON到图像到音频和视频的流媒体下载的各种请求:

在iOS上,我广泛使用AFNetworking项目。Android上有类似的库吗? 我已经阅读了Square的OkHTTP和Retrofit,以及Volley,但还没有使用它们开发的经验。我希望有人能够为每种方法提供一些最佳用例的具体示例。从我所读到的,OkHTTP似乎是三个中最健壮的,并且可以处理这个项目的需求(上面提到过)。


当前回答

Retrofit 1.9.0 vs RoboSpice

我在我的应用程序中使用这两种。

当我解析嵌套的JSON类时,Robospice比Retrofit工作得更快。因为Spice Manger会为你做任何事。在Retrofit中,您需要创建GsonConverter并反序列化它。

我在同一个活动中创建了两个片段,并使用两个相同类型的url同时调用。

09-23 20:12:32.830  16002-16002/com.urbanpro.seeker E/RETROFIT﹕   RestAdapter Init
09-23 20:12:32.833  16002-16002/com.urbanpro.seeker E/RETROFIT﹕ calling the method
09-23 20:12:32.837  16002-16002/com.urbanpro.seeker E/ROBOSPICE﹕ initialzig spice manager
09-23 20:12:32.860  16002-16002/com.urbanpro.seeker E/ROBOSPICE﹕ Executing the method
09-23 20:12:33.537  16002-16002/com.urbanpro.seeker E/ROBOSPICE﹕ on SUcceess
09-23 20:12:33.553  16002-16002/com.urbanpro.seeker E/ROBOSPICE﹕ gettting the all contents
09-23 20:12:33.601  16002-21819/com.urbanpro.seeker E/RETROFIT﹕ deseriazation starts
09-23 20:12:33.603  16002-21819/com.urbanpro.seeker E/RETROFIT﹕ deseriazation ends

其他回答

RoboSpice Vs. Volley

从https://groups.google.com/forum/ # !主题/ robospice / QwVCfY_glOQ

RoboSpice(RS) is service based and more respectful of Android philosophy than Volley. Volley is thread based and this is not the way background processing should take place on Android. Ultimately, you can dig down both libs and find that they are quite similar, but our way to do background processing is more Android oriented, it allow us, for instance, to tell users that RS is actually doing something in background, which would be hard for volley (actually it doesn't at all). RoboSpice and volley both offer nice features like prioritization, retry policies, request cancellation. But RS offers more : a more advanced caching and that's a big one, with cache management, request aggregation, more features like repluging to a pending request, dealing with cache expiry without relying on server headers, etc. RoboSpice does more outside of UI Thread : volley will deserialize your POJOs on the main thread, which is horrible to my mind. With RS your app will be more responsive. In terms of speed, we definitely need metrics. RS has gotten super fast now, but still we don't have figure to put here. Volley should theoretically be a bit faster, but RS is now massively parallel... who knows ? RoboSpice offers a large compatibility range with extensions. You can use it with okhttp, retrofit, ormlite (beta), jackson, jackson2, gson, xml serializer, google http client, spring android... Quite a lot. Volley can be used with ok http and uses gson. that's it. Volley offers more UI sugar that RS. Volley provides NetworkImageView, RS does provide a spicelist adapter. In terms of feature it's not so far, but I believe Volley is more advanced on this topic. More than 200 bugs have been solved in RoboSpice since its initial release. It's pretty robust and used heavily in production. Volley is less mature but its user base should be growing fast (Google effect). RoboSpice is available on maven central. Volley is hard to find ;)

看看Volley透视图,这里有一些适合您需求的优点:

一方面,Volley完全专注于处理单个的小HTTP请求。因此,如果您的HTTP请求处理有一些怪癖,Volley可能为您提供了一个钩子。另一方面,如果您在图像处理方面有一个怪癖,那么您拥有的唯一真正的钩子就是ImageCache。“不是没有,但也不多!””。但它有更多的其他优点,比如一旦你定义了你的请求,从一个片段或活动中使用它们是轻松的,不像并行AsyncTasks

Volley的优点和缺点:

那么Volley的优点是什么呢?

The networking part isn’t just for images. Volley is intended to be an integral part of your back end. For a fresh project based off of a simple REST service, this could be a big win. NetworkImageView is more aggressive about request cleanup than Picasso, and more conservative in its GC usage patterns. NetworkImageView relies exclusively on strong memory references, and cleans up all request data as soon as a new request is made for an ImageView, or as soon as that ImageView moves offscreen. Performance. This post won’t evaluate this claim, but they’ve clearly taken some care to be judicious in their memory usage patterns. Volley also makes an effort to batch callbacks to the main thread to reduce context switching. Volley apparently has futures, too. Check out RequestFuture if you’re interested. If you’re dealing with high-resolution compressed images, Volley is the only solution here that works well. Volley can be used with Okhttp (New version of Okhttp supports NIO for better performance ) Volley plays nice with the Activity life cycle.

截击的问题: 由于Volley是新的,一些东西还不支持,但它是固定的。

Multipart Requests (Solution: https://github.com/vinaysshenoy/enhanced-volley) status code 201 is taken as an error, Status code from 200 to 207 are successful responses now.(Fixed: https://github.com/Vinayrraj/CustomVolley) Update: in latest release of Google volley, the 2XX Status codes bug is fixed now!Thanks to Ficus Kirkpatrick! it's less documented but many of the people are supporting volley in github, java like documentation can be found here. On android developer website, you may find guide for Transmitting Network Data Using Volley. And volley source code can be found at Google Git To solve/change Redirect Policy of Volley Framework use Volley with OkHTTP (CommonsWare mentioned above)

你也可以阅读这比较Volley的图像加载与毕加索

改造:

它是由Square发布的,它提供了非常容易使用的REST API(更新:瞧!蔚来汽车支持)

改造的优点:

与Volley相比,Retrofit的REST API代码更简洁,并提供了 优秀的API文档,在社区中有很好的支持! 它很容易添加到项目中。 我们可以将它用于任何序列化库,并进行错误处理。

更新:

There are plenty of very good changes in Retrofit 2.0.0-beta2 version 1.6 of Retrofit with OkHttp 2.0 is now dependent on Okio to support java.io and java.nio which makes it much easier to access, store and process your data using ByteString and Buffer to do some clever things to save CPU and memory. (FYI: This reminds me of the Koush's OIN library with NIO support!) We can use Retrofit together with RxJava to combine and chain REST calls using rxObservables to avoid ugly callback chains (to avoid callback hell!!).

版本1.6的缺点:

内存相关的错误处理功能不太好(在旧版本的Retrofit/OkHttp中),不确定它是否在Java NIO支持的Okio中得到了改进。 如果我们使用这个方法,最小的线程帮助可能导致回调地狱 以不恰当的方式

(以上所有缺点都在新版本的Retrofit 2.0 beta中得到解决)

========================================================================

更新:

Android Async vs Volley vs Retrofit性能基准(毫秒,值越低越好):

Library One Discussion Dashboard (7 requests) 25 Discussions
AsyncTask 941 ms 4,539 ms 13,957 ms
Volley 560 ms 2,202 ms 4,275 ms
Retrofit 312 ms 889 ms 1,059 ms

(供参考,上面的改装基准信息将改善java NIO支持,因为新版本的OKhttp依赖于NIO Okio库)

In all three tests with varying repeats (1 – 25 times), Volley was anywhere from 50% to 75% faster. Retrofit clocked in at an impressive 50% to 90% faster than the AsyncTasks, hitting the same endpoint the same number of times. On the Dashboard test suite, this translated into loading/parsing the data several seconds faster. That is a massive real-world difference. In order to make the tests fair, the times for AsyncTasks/Volley included the JSON parsing as Retrofit does it for you automatically. RetroFit Wins in benchmark test! In the end, we decided to go with Retrofit for our application. Not only is it ridiculously fast, but it meshes quite well with our existing architecture. We were able to make a parent Callback Interface that automatically performs error handling, caching, and pagination with little to no effort for our APIs. In order to merge in Retrofit, we had to rename our variables to make our models GSON compliant, write a few simple interfaces, delete functions from the old API, and modify our fragments to not use AsyncTasks. Now that we have a few fragments completely converted, it’s pretty painless. There were some growing pains and issues that we had to overcome, but overall it went smoothly. In the beginning, we ran into a few technical issues/bugs, but Square has a fantastic Google+ community that was able to help us through it.

什么时候使用凌空?!

当我们需要加载图像以及使用REST api时,我们可以使用Volley !,网络呼叫排队系统需要同时处理多个n/w请求!Volley也有更好的内存相关错误处理比Retrofit!

OkHttp可以使用Volley, Retrofit默认使用OkHttp !它有SPDY支持,连接池,磁盘缓存,透明压缩!最近,它通过Okio库获得了java NIO的一些支持。

来源:Josh Ruesch先生的volley-vs-retrofit

注意:关于流,它取决于你想要什么类型的流,比如RTSP/RTCP。

添加到已接受的答案和LOG_TAG所说的....对于Volley在后台线程中解析您的数据,您必须子类Request<YourClassName>,因为onResponse方法在主线程上被调用,如果您的响应很大,在主线程上解析可能会导致UI延迟。 在这里阅读如何做到这一点。

我希望有人能够为每种方法提供一些最佳用例的具体示例。

如果您正在与Web服务通信,请使用Retrofit。如果您正在下载图像,请使用毕加索对等库。如果需要在Retrofit/Picasso之外执行HTTP操作,请使用OkHTTP。

Volley与Retrofit + Picasso大致竞争。好的方面是,它是一个库。缺点是,它是一个没有文档的、不受支持的、“把代码扔到墙上,然后在上面做一个I|O演示”的库。

编辑-排射现在正式支持谷歌。请参考谷歌开发者指南

据我所知,OkHTTP似乎是这三个中最健壮的

如果可以,Retrofit会自动使用OkHTTP。杰克·沃顿有个要点能把Volley和OkHTTP联系起来。

并能处理这个项目的要求(如上所述)。

根据“流媒体”的传统定义,你可能不会使用它们中的任何一个来“流式下载音频和视频”。相反,Android的媒体框架将为你处理这些HTTP请求。

也就是说,如果您打算尝试自己的基于http的流,OkHTTP应该处理这种情况;我不记得Volley会如何处理这种情况。无论是Retrofit还是Picasso都不是为此而设计的。

还有另一个选择: https://github.com/apptik/jus

它像Volley一样是模块化的,但更多的扩展和文档正在改进,支持不同的HTTP堆栈和开箱即用的转换器 它有一个模块来生成服务器API接口映射,比如Retrofit 它还支持JavaRx

以及许多其他方便的功能,如标记,变形金刚等。