How to use AutoValue with Retrofit 2?

问题:

I've got AutoValue (and the android-apt plugin) working in a project, and I'm aware of Ryan Harter's gson extension for AutoValue, but how do I hook Retrofit 2 up to use the extension and factory method on the abstract class?

String grantType = "password";
Call<SignIn> signInCall = retrofitApi.signIn(email, password, grantType);
signInCall.enqueue(callback);

eg here I would like to use AutoValue with the SignIn JSON model object to enforce immutability but how do I hook up Retrofit (or perhaps more specifically Gson) to the immutable, AutoValue model class?

回答1:

[update] The library have changed a bit, check more here: https://github.com/rharter/auto-value-gson

I was able to make it work like this. I hope it will help you.

• Import in your gradle app file

  apt 'com.ryanharter.auto.value:auto-value-gson:0.3.1'

• Create object with autovalue:

  @AutoValue public abstract class SignIn {    
      @SerializedName("signin_token") public abstract String signinToken();
      @SerializedName("user") public abstract Profile profile();
  
      public static TypeAdapter<SignIn> typeAdapter(Gson gson) {
          return new AutoValue_SignIn.GsonTypeAdapter(gson);
      }
  }
  

• Create your Type Adapter Factory (Skip if using version > 0.3.0)

  public class AutoValueGsonTypeAdapterFactory implements TypeAdapterFactory {
  
      public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
          Class<? super T> rawType = type.getRawType();
  
          if (rawType.equals(SignIn.class)) {
              return (TypeAdapter<T>) SignIn.typeAdapter(gson);
          } 
  
          return null;
      }
  }
  

• Create your Gson converter with your GsonBuilder

  GsonConverterFactory gsonConverterFactory = GsonConverterFactory.create(
          new GsonBuilder()
                  .registerTypeAdapterFactory(new AutoValueGsonTypeAdapterFactory())
                  .create());
  

• Add it to your retrofit builder

  Retrofit retrofit = new Retrofit
          .Builder()
          .addConverterFactory(gsonConverterFactory)
          .baseUrl("http://url.com/")
          .build()
  

• Do your request

• Enjoy

Bonus live template:
In your autovalue class, type avtypeadapter then autocomplete to generate the type adapter code. To work you need to add this as a live template in Android Studio.

public static TypeAdapter<$class$> typeAdapter(Gson gson) {
    return new AutoValue_$class$.GsonTypeAdapter(gson);
}

How to create and use the live template.

回答2:

Here's a Gist by Jake Wharton for a Gson TypeAdapterFactory that just requires you add an annotation to all of your AutoValue classes that require working with Gson https://gist.github.com/JakeWharton/0d67d01badcee0ae7bc9

Works great for me.

Here's some proguard help too..

-keep class **.AutoValue_*
-keepnames @yourpackage.AutoGson class *