2. Tutorials
  3. Retrofit — How to Integrate XML Converter

Retrofit — How to Integrate XML Converter

This post is all about how to integrate an XML converter with Retrofit. Before we go on, let's have a look at the other articles in the series of Retrofit posts.

Retrofit Series Overview

  1. Getting Started and Creating an Android Client
  2. Basics of API Description
  3. Creating a Sustainable Android Client
  4. URL Handling, Resolution and Parsing
  5. How to Change API Base Url at Runtime
  6. Multiple Server Environments (Develop, Staging, Production)
  7. Share OkHttp Client and Converters between Retrofit Instances
  8. Upgrade Guide from 1.9
  9. Beyond Android: Retrofit for Java Projects
  10. How to use OkHttp 3 with Retrofit 1
  1. Synchronous and Asynchronous Requests
  2. Send Objects in Request Body
  3. Add Custom Request Header
  4. Manage Request Headers in OkHttp Interceptor
  5. Dynamic Request Headers with @HeaderMap
  6. Multiple Query Parameters of Same Name
  7. Optional Query Parameters
  8. Send Data Form-Urlencoded
  9. Send Data Form-Urlencoded Using FieldMap
  10. How to Add Query Parameters to Every Request
  11. Add Multiple Query Parameter With QueryMap
  12. How to Use Dynamic Urls for Requests
  13. Constant, Default and Logic Values for POST and PUT Requests
  14. Cancel Requests
  15. Reuse and Analyze Requests
  16. Optional Path Parameters
  17. How to Send Plain Text Request Body
  18. Customize Network Timeouts
  19. How to Trust Unsafe SSL certificates (Self-signed, Expired)
  20. Dynamic Endpoint-Dependent Interceptor Actions
  21. How to Update Objects on the Server (PUT vs. PATCH)
  22. How to Delete Objects on the Server
  1. Ignore Response Payload with Call<Void>
  2. Receive Plain-String Responses
  3. Crawl HTML Responses with jspoon (Wikipedia Example)
  4. Loading Data into RecyclerView and CardView
  1. Simple Error Handling
  2. Error Handling for Synchronous Requests
  3. Catch Server Errors Globally with Response Interceptor
  4. How to Detect Network and Conversion Errors in onFailure
  1. Log Requests and Responses
  2. Enable Logging for Development Builds Only
  3. Log Network Traffic with Stetho and Chrome Developer Tools
  4. Using the Log Level to Debug Requests
  5. Analyze Network Traffic with Android Studio Profiler
  6. Debug and Compare Requests with RequestBin
  1. Introduction to Call Adapters
  2. Custom Call Adapter to Separate OnResponse Callback
  3. How to Integrate RxJava 1.x Call Adapter
  4. How to Integrate RxJava 2.x Call Adapter
  5. How to Integrate Guava Call Adapter
  6. Custom Call Adapter to Separate Network and Gson Errors
  1. Pagination Using Query Parameter
  2. Pagination Using Link Header and Dynamic Urls (Like GitHub)
  3. Pagination Using Range Header Fields (Like Heroku)
  1. How to Upload Files to Server
  2. How to Upload Multiple Files to Server
  3. How to Upload a Dynamic Amount of Files to Server
  4. Upload Files with Progress
  5. Passing Multiple Parts Along a File with @PartMap
  6. How to Download Files from Server
  7. Download Files with Progress Updates
  8. How to Upload Files to Server
  1. Basic Authentication on Android
  2. Token Authentication on Android
  3. OAuth on Android
  4. Hawk Authentication on Android
  5. How to Refresh an Access Token
  1. Activate Response Caching (Etag, Last-Modified)
  2. Check Response Origin (Network, Cache, or Both)
  3. Force Server Cache Support with Response Interceptor
  4. Support App Offline Mode by Accessing Response Caches
  5. Analyze Cache Files
  1. Basics of Mocking Server Responses
  2. Customizing Network Behavior of Mocked Server Responses
  3. Mock APIs with JsonServer
  1. Callbacks
  2. Annotations
  3. Fluent Interface with Builders

Define XML Converter

We assume you’re familiar with the basics of Retrofit and you know how to configure Retrofits RestAdapter (Retrofit in Retrofit 2). If not, please have a look at the getting started post in this series.

Here, we’ll show you how to integrate an XML converter to map HTTP responses from XML to Java objects.

Define Gradle Dependency

First stop is the build.gradle file. The Retrofit project already has an XML converter available which you need to add to your project as a peer-dependency. Have a look at our previous post about how to create or define your custom response converter if you want to know more about existing converters for Retrofit.

Here we go, define the dependency in your build.gradle.

Retrofit 1.9

dependencies {  
    // Retrofit XML converter (Simple)
    compile 'com.squareup.retrofit:converter-simplexml:1.9.0'
}

Retrofit 2

dependencies {  
    // Retrofit XML converter (Simple)
    compile 'com.squareup.retrofit2:converter-simplexml:2.5.0'
}

Once you added the dependency for the SimpleXML converter to your build.gradle file, sync the project and wait for Android Studio to finish the process. Afterwards, proceed with the next steps described in the section below :)

XMLConverter feat. RestAdapter/Retrofit

Now, we have to define the SimpleXMLConverter as converter for the RestAdapter (Retrofit in Retrofit 2).

Retrofit 1.9

RestAdapter adapter = new RestAdapter.Builder()  
    .setClient(new OkClient(new OkHttpClient())
    .setEndpoint(yourBaseUrl)
    .setConverter(new SimpleXMLConverter())
    .build();

Just pass the new SimpleXMLConverter() constructor to the .setConverter() method to override the default converter (GSON).

Retrofit 2

Retrofit retrofit = new Retrofit.Builder()  
    .baseUrl(API_BASE_URL)
    .client(new OkHttpClient())
    .addConverterFactory(SimpleXmlConverterFactory.create())
    .build();

The handling of response converters changed in Retrofit 2. You don’t override existing converters. That results in the possibility to define multiple converters for your Retrofit instance. Internally, Retrofit will try to parse the response with the first added converter. If that fails, it will proceed with the next one, and so on …

Objects Love Annotations

Retrofit will map your XML response to Java objects, doesn’t matter which XML converter you’re using. Therefore, we need to annotate the Java objects for correct tag to property mapping.

We’ll use the Task class below and add annotations to map the corresponding tasks.xml file.

tasks.xml

This XML file does not appear to have any style information associated with it. The document tree is shown below.

<rss xmlns:atom="http://www.w3.org/2005/Atom" version="2.0">  
    <task>
        <id link="http://url-to-link.com/task-id">1</id>
        <title>Retrofit XML Converter Blog Post</title>
        <description>Write blog post: XML Converter with Retrofit</description>
        <language>de-de</language>
    </task>
</rss>

Task

@Root(name = "task")
public class Task {  
    @Element(name = "id")
    private long id;

    @Element(name = "title")
    private String title;

    @Element(name = "description")
    private String description;

    @Attribute(required = false)
    private String link;

    public Task() {}
}

The annotations define the element name which gets mapped to the class property. Within the example, all elements have the same name in the XML file and the Java class. For sure, you can use a different naming and just put the element name to the @Element annotation.

That’s it. Just go ahead and make your request :)

Feel free to contact us @futurestud_io if you run into any problem. We’re happy to help.

Additional Resources

Marcus Pöhls

Marcus is a fullstack JS developer. He’s passionate about the hapi framework for Node.js and loves to build web apps and APIs. Creator of Futureflix and the “learn hapi” learning path.

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