Two-part question from an iOS developer learning Android, working on an Android project that will make a variety of requests from JSON to image to streaming download of audio and video:
On iOS I have used the AFNetworking project extensively. Is there an equivalent library for Android?
I’ve read up on OkHTTP and Retrofit by Square, as well as Volley but don’t yet have experience developing with them. I’m hoping someone could provide some concrete examples of best use cases for each. From what I’ve read, seems like OkHTTP is the most robust of the three, and could handle the requirements of this project (mentioned above).
I’m hoping someone can provide some concrete examples of best use cases for each.
Use Retrofit if you are communicating with a Web service. Use the peer library Picasso if you are downloading images. Use OkHTTP if you need to do HTTP operations that lie outside of Retrofit/Picasso.
Volley roughly competes with Retrofit + Picasso. On the plus side, it is one library. On the minus side, it is
one undocumented, an unsupported, “throw the code over the wall and do an I|O presentation on it” library.
EDIT – Volley is now officially supported by Google. Kindly refer Google Developer Guide
From what I’ve read, seems like OkHTTP is the most robust of the 3
Retrofit uses OkHTTP automatically if available. There is a Gist from Jake Wharton that connects Volley to OkHTTP.
and could handle the requirements of this project (mentioned above).
Probably you will use none of them for “streaming download of audio and video”, by the conventional definition of “streaming”. Instead, Android’s media framework will handle those HTTP requests for you.
That being said, if you are going to attempt to do your own HTTP-based streaming, OkHTTP should handle that scenario; I don’t recall how well Volley would handle that scenario. Neither Retrofit nor Picasso are designed for that.
Looking at the Volley perspective here are some advantages for your requirement:
Volley, on one hand, is totally focused on handling individual, small HTTP requests. So if your HTTP request handling has some quirks, Volley probably has a hook for you. If, on the other hand, you have a quirk in your image handling, the only real hook you have is ImageCache. “It’s not nothing, but it’s not a lot!, either”. but it has more other advantages like Once you define your requests, using them from within a fragment or activity is painless unlike parallel AsyncTasks
Pros and cons of Volley:
So what’s nice about Volley?
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
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.
Problems With Volley:
Since Volley is new, few things are not supported yet, but it’s fixed.
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
Also you can read this Comparing Volley’s image loading with Picasso
It’s released by Square, This offers very easy to use REST API’s (Update: Voila! with NIO support)
Pros of Retrofit:
Compared to Volley, Retrofit’s REST API code is brief and provides
excellent API documentation and has good support in communities!
It is very easy to add into the projects.
We can use it with any serialization library, with error handling.
– 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!!).
Cons of Retrofit for version 1.6:
Memory related error handling functionality is not good (in older versions of Retrofit/OkHttp) not sure if it’s improved with the Okio with Java NIO support.
Minimum threading assistance can result call back hell if we use this
in an improper way.
(All above Cons have been solved in the new version of Retrofit 2.0 beta)
Android Async vs Volley vs Retrofit performance benchmarks (milliseconds, lower value is better):
(FYI above Retrofit Benchmarks info will improve with java NIO support because the new version of OKhttp is dependent on NIO Okio library)
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.
When to use Volley?!
We can use Volley when we need to load images as well as consuming REST APIs!, network call queuing system is needed for many n/w request at the same time! also Volley has better memory related error handling than Retrofit!
OkHttp can be used with Volley, Retrofit uses OkHttp by default! It has SPDY support, connection pooling, disk caching, transparent compression! Recently, it has got some support of java NIO with Okio library.
Source, credit: volley-vs-retrofit by Mr. Josh Ruesch
Note: About streaming it depends on what type of streaming you want like RTSP/RTCP.
RoboSpice Vs. Volley
- 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 😉
AFNetworking for Android:
Fast Android Networking Library supports all types of HTTP/HTTPS request like GET, POST, DELETE, HEAD, PUT, PATCH
Fast Android Networking Library supports downloading any type of file
Fast Android Networking Library supports uploading any type of file (supports multipart upload)
Fast Android Networking Library supports cancelling a request
Fast Android Networking Library supports setting priority to any request (LOW, MEDIUM, HIGH, IMMEDIATE)
Fast Android Networking Library supports RxJava
As it uses OkHttp as a networking layer, it supports:
Fast Android Networking Library supports HTTP/2 support allows all requests to the same host to share a socket
Fast Android Networking Library uses connection pooling which reduces request latency (if HTTP/2 isn’t available)
Transparent GZIP shrinks download sizes
Fast Android Networking Library supports response caching which avoids the network completely for repeat requests
Thanks: The library is created by me
Async HTTP client loopj vs. Volley
The specifics of my project are small HTTP REST requests, every 1-5 minutes.
I using an async HTTP client (1.4.1) for a long time. The performance is better than using the vanilla Apache httpClient or an HTTP URL connection. Anyway, the new version of the library is not working for me: library inter exception cut chain of callbacks.
Reading all answers motivated me to try something new. I have chosen the Volley HTTP library.
After using it for some time, even without tests, I see clearly that the response time is down to 1.5x, 2x Volley.
Maybe Retrofit is better than an async HTTP client? I need to try it.
But I’m sure that Volley is not for me.
Just to add a bit to the discussion from my experience working with Volley:
Volley does not handle streaming uploads or downloads in any sense. That is, the entire request body has to be in memory and you cannot use an
OutputStreamto write the request body to the underlying socket, nor can you use an
InputStreamto read the response body, as basic
HttpURLConnectiondoes. So, Volley is a poor choice for uploading or downloading large files. Your requests and responses should be small. This is one of the biggest limitations of Volley that I have personally encountered. For what it’s worth, OkHttp does have interfaces for working with streams.
The lack of official documentation is annoying, although I have been able to work around that by reading the source code, which is pretty easy to follow. What is more bothersome is that, as far as I can tell, Volley has no official release versions and no Maven or Gradle artifact, and therefore managing it as a dependency becomes more of a headache than, say, any of the libraries Square has released. You just clone a repo, build a jar, and you’re on your own. Looking for a bug fix? Fetch and hope it’s there. You might get some other stuff, too; it won’t be documented. In my opinion, this effectively means that Volley is an unsupported 3rd party library, even though the code base is reasonably active. Caveat emptor.
As a nit, having the Content-Type tied to the class/request type (JsonObjectRequest, ImageRequest, etc.) is kind of awkward and reduces the flexibility of the calling code a bit, as you are tied to Volley’s existing Request type hierarchy. I like the straightforwardness of just setting Content-Type as a header like any other (don’t do this with Volley, by the way; you’ll end up with two Content-Type headers!). That’s just my personal opinion, though, and it can be worked around.
That is not to say that Volley does not have some useful features. It certainly does. Easily customizable retry policies, transparent caching, a cancellation API, and support for request scheduling and concurrent connections are great features. Just know that it’s not intended for all HTTP use cases (see item 1 above), and that there are some headaches involved in putting Volley into production use in your app (item 2).
I’ve recently found a lib called ion that brings a little extra to the table.
ion has built-in support for image download integrated with ImageView, JSON (with the help of GSON), files and a very handy UI threading support.
I’m using it on a new project and so far the results have been good. Its use is much simpler than Volley or Retrofit.
Adding to the accepted answer and what LOG_TAG said….for Volley to parse your data in a background thread you must subclass
Request<YourClassName> as the
onResponse method is called on the main thread and parsing on the main thread may cause the UI to lag if your response is big.
Read here on how to do that.
Retrofit 1.9.0 vs. RoboSpice
I am using both in my app.
Robospice works faster than Retrofit whenever I parse the nested JSON class. Because Spice Manger will do everything for you. In Retrofit you need to create GsonConverter and deserialize it.
I created two fragments in the same activity and called the same time with two same kind of URLs.
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
And yet another option:
- It is modular like Volley, but more extended and documentation is improving, supporting different HTTP stacks and converters out of the box
- It has a module to generate server API interface mappings like Retrofit
- It also has JavaRx support
And many other handy features like markers, transformers, etc.