无法在Android Retrofit库中为我的课程创建转换器 [英] Unable to create converter for my class in Android Retrofit library

问题描述

从使用Volley迁移到Retrofit，我已经有了用于将JSONObject响应转换为实现gson注释的对象的gson类。当我尝试使用retrofit进行http get请求时，但是我的应用程序崩溃并出现此错误：

 无法启动活动ComponentInfo {com.lightbulb.pawesome / com.example.sample.retrofit.SampleActivity}：java.lang.IllegalArgumentException：无法为类com.lightbulb.pawesome.model.Pet创建转换器
为方法GitHubService.getResponse 
  

我遵循 retrofit 网站，我想出了这些实现：

这是我尝试执行复古http请求的活动：

  public class SampleActivity extends AppCompatActivity {
 @Override 
 protected void onCreate（Bundle savedInstanceState）{
 super.onCreate （savedInstanceState）; 
 setContentView（R.layout.activity_sample）; 
 
 Retrofit retrofit = new Retrofit.Builder（）
 .baseUrl（** sample base url here **）
 .build（）; 
 
 GitHubService service = retrofit.create（GitHubService.class）; 
呼叫< Pet> callPet = service.getResponse（41，40）; 
 callPet.enqueue（new Callback< Pet>（）{
 @Override 
 public void onResponse（Response< Pet> response）{
 Log.i（Response，response .toString（））; 
} 
 
 @Override 
 public void onFailure（Throwable t）{
 Log.i（Failure，t.toString（） ）; 
} 
}）; 
尝试{
 callPet.execute（）; 
} catch（IOException e）{
 e.printStackTrace（）; 
} 
 
} 
} 
  

我的界面它变成了我的API

  public interface GitHubService {
 @GET（/ ** sample here ** / {petId} / {otherPet}）
呼叫< Pet> getResponse（@Path（petId）String userId，@Path（otherPet）String otherPet）; 
} 
  

最后，Pet类应该是响应者：

  public class Pet implements Parcelable {
 
 public static final String ACTIVE =1; 
 public static final String NOT_ACTIVE =0; 
 
 @SerializedName（is_active）
 @Expose 
 private String isActive; 
 @SerializedName（pet_id）
 @Expose 
 private String petId; 
 @Expose 
私人字符串名称; 
 @Expose 
私人字符串性别; 
 @Expose 
私人字符串年龄; 
 @Expose 
私人字符串品种; 
 @SerializedName（profile_picture）
 @Expose 
 private String profilePicture; 
 @SerializedName（confirmation_status）
 @Expose 
 private String confirmationStatus; 
 $ b $ ** 
 * 
 * @return 
 * confirmationStatus 
 * / 
 public String getConfirmationStatus（）{
返回confirmationStatus; 
} 
 
 / ** 
 * 
 * @param confirmationStatus 
 * confirmation_status 
 * / 
 public void setConfirmationStatus（字符串confirmationStatus）{
 this.confirmationStatus = confirmationStatus; 
 
 $ b / ** 
 * 
 * @return 
 * isActive 
 * / 
 public String getIsActive（） {
 return isActive; 
} 
 
 / ** 
 * 
 * @param isActive 
 * is_active 
 * / 
 public void setIsActive字符串isActive）{
 this.isActive = isActive; 
 
 $ b / ** 
 * 
 * @return 
 * petId 
 * / 
 public String getPetId（） {
 return petId; 
} 
 
 / ** 
 * 
 * @param petId 
 * pet_id 
 * / 
 public void setPetId字符串petId）{
 this.petId = petId; 
 
 $ b / ** 
 * 
 * @return 
 *名称
 * / 
 public String getName（） {
返回姓名; 
 
 $ b / ** 
 * 
 * @param名称
 *名称
 * / 
 public void setName（字符串名称）{
 this.name = name; 
 
 $ b / ** 
 * 
 * @return 
 *性别
 * / 
 public String getGender（） {
返回性别; 
} 
 
 / ** 
 * 
 * @param gender 
 *性别
 * / 
 public void setGender字符串性别）{
 this.gender = gender; 
 
 $ b / ** 
 * 
 * @return 
 *年龄
 * / 
 public String getAge（） {
回归年龄; 
} 
 
 / ** 
 * 
 * @参数年龄
 *年龄
 * / 
 public void setAge字符串年龄）{
 this.age =年龄; 
 
 $ b / ** 
 * 
 * @return 
 *品种
 * / 
 public String getBreed（） {
返回品种; 
} 
 
 / ** 
 * 
 * @param繁殖
 *繁殖
 * / 
 public void setBreed字符串品种）{
 this.breed =品种; 
 
 $ b / ** 
 * 
 * @return 
 * profilePicture 
 * / 
 public String getProfilePicture（） {
 return profilePicture; 
} 
 $ b $ ** 
 * 
 * @param profilePicture 
 * profile_picture 
 * / 
 public void setProfilePicture（ String profilePicture）{
 this.profilePicture = profilePicture; 
 
 
 
保护宠物（Parcel in）{
 isActive = in.readString（）; 
 petId = in.readString（）; 
 name = in.readString（）; 
 gender = in.readString（）; 
 age = in.readString（）; 
 breed = in.readString（）; 
 profilePicture = in.readString（）; 
} 
 
 @Override 
 public int describeContents（）{
 return 0; 
 
 $ b @Override 
 public void writeToParcel（Parcel dest，int flags）{
 dest.writeString（isActive）; 
 dest.writeString（petId）; 
 dest.writeString（name）; 
 dest.writeString（gender）; 
 dest.writeString（age）; 
 dest.writeString（breed）; 
 dest.writeString（profilePicture）; 
} 
 
 @SuppressWarnings（unused）
 public static final Parcelable.Creator< Pet> CREATOR = new Parcelable.Creator< Pet>（）{
 @Override 
 public Pet createFromParcel（Parcel in）{
 return new Pet（in）; 
} 
 
 @Override 
 public Pet [] newArray（int size）{
 return new Pet [size]; 
} 
}; 
 
  

解决方案

c> 2.0.0 ，默认的转换器是一个gson转换器，但是在 2.0.0 中，后来默认的转换器是 ResponseBody 。从文档：

默认情况下，Retrofit只能将HTTP正文序列化为OkHttp的
ResponseBody

code>类型，它只能接受它的 RequestBody 类型为
@Body 。 2.0.0 + 中，你需要明确指定你想要一个Gson转换器：

 改造retrofit = new Retrofit.Builder（）
 .baseUrl（** sample base url here ** ）
 .addConverterFactory（GsonConverterFactory.create（））
 .build（）; 
  

您还需要将以下依赖项添加到您的gradle文件中：

  compile'c​​om.squareup.retrofit2：converter-gson：2.1.0'
  

使用与您的改造相同的版本。以上符合这种改造依赖：

$ p $ compile（'com.squareup.retrofit2：retrofit：2.1.0'）


另外，请注意，在撰写本文时，翻新文档并未完全更新，这就是为什么该示例让您深入了解麻烦。从文档：

注意：该网站仍在为新的2.0 API进行扩展。

Im migrating from using Volley to Retrofit, I already have gson class that I used before for converting JSONObject reponse to a object that implements gson annotations. When I'm trying to make http get request using retrofit but then my app crashes with this error :

 Unable to start activity ComponentInfo{com.lightbulb.pawesome/com.example.sample.retrofit.SampleActivity}: java.lang.IllegalArgumentException: Unable to create converter for class com.lightbulb.pawesome.model.Pet
    for method GitHubService.getResponse

Im following the guide in retrofit site and I come up with these implementations :

This is my activity where I am trying to execute the retro http request:

public class SampleActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_sample);

        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl("**sample base url here**")
                .build();

        GitHubService service = retrofit.create(GitHubService.class);
        Call<Pet> callPet = service.getResponse("41", "40");
        callPet.enqueue(new Callback<Pet>() {
            @Override
            public void onResponse(Response<Pet> response) {
                Log.i("Response", response.toString());
            }

            @Override
            public void onFailure(Throwable t) {
                Log.i("Failure", t.toString());
            }
        });
        try{
            callPet.execute();
        } catch (IOException e){
            e.printStackTrace();
        }

    }
}

My interface which turned to be my API

public interface GitHubService {
    @GET("/ **sample here** /{petId}/{otherPet}")
    Call<Pet> getResponse(@Path("petId") String userId, @Path("otherPet") String otherPet);
}

And finally the Pet class which should be the reponse:

public class Pet implements Parcelable {

    public static final String ACTIVE = "1";
    public static final String NOT_ACTIVE = "0";

    @SerializedName("is_active")
    @Expose
    private String isActive;
    @SerializedName("pet_id")
    @Expose
    private String petId;
    @Expose
    private String name;
    @Expose
    private String gender;
    @Expose
    private String age;
    @Expose
    private String breed;
    @SerializedName("profile_picture")
    @Expose
    private String profilePicture;
    @SerializedName("confirmation_status")
    @Expose
    private String confirmationStatus;

    /**
     *
     * @return
     * The confirmationStatus
     */
    public String getConfirmationStatus() {
        return confirmationStatus;
    }

    /**
     *
     * @param confirmationStatus
     * The confirmation_status
     */
    public void setConfirmationStatus(String confirmationStatus) {
        this.confirmationStatus = confirmationStatus;
    }

    /**
     *
     * @return
     * The isActive
     */
    public String getIsActive() {
        return isActive;
    }

    /**
     *
     * @param isActive
     * The is_active
     */
    public void setIsActive(String isActive) {
        this.isActive = isActive;
    }

    /**
     *
     * @return
     * The petId
     */
    public String getPetId() {
        return petId;
    }

    /**
     *
     * @param petId
     * The pet_id
     */
    public void setPetId(String petId) {
        this.petId = petId;
    }

    /**
     *
     * @return
     * The name
     */
    public String getName() {
        return name;
    }

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

    /**
     *
     * @return
     * The gender
     */
    public String getGender() {
        return gender;
    }

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

    /**
     *
     * @return
     * The age
     */
    public String getAge() {
        return age;
    }

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

    /**
     *
     * @return
     * The breed
     */
    public String getBreed() {
        return breed;
    }

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

    /**
     *
     * @return
     * The profilePicture
     */
    public String getProfilePicture() {
        return profilePicture;
    }

    /**
     *
     * @param profilePicture
     * The profile_picture
     */
    public void setProfilePicture(String profilePicture) {
        this.profilePicture = profilePicture;
    }


    protected Pet(Parcel in) {
        isActive = in.readString();
        petId = in.readString();
        name = in.readString();
        gender = in.readString();
        age = in.readString();
        breed = in.readString();
        profilePicture = in.readString();
    }

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(isActive);
        dest.writeString(petId);
        dest.writeString(name);
        dest.writeString(gender);
        dest.writeString(age);
        dest.writeString(breed);
        dest.writeString(profilePicture);
    }

    @SuppressWarnings("unused")
    public static final Parcelable.Creator<Pet> CREATOR = new Parcelable.Creator<Pet>() {
        @Override
        public Pet createFromParcel(Parcel in) {
            return new Pet(in);
        }

        @Override
        public Pet[] newArray(int size) {
            return new Pet[size];
        }
    };
}

解决方案

Prior to 2.0.0, the default converter was a gson converter, but in 2.0.0 and later the default converter is ResponseBody. From the docs:

By default, Retrofit can only deserialize HTTP bodies into OkHttp's ResponseBody type and it can only accept its RequestBody type for @Body.

In 2.0.0+, you need to explicitly specify you want a Gson converter:

Retrofit retrofit = new Retrofit.Builder()
    .baseUrl("**sample base url here**")
    .addConverterFactory(GsonConverterFactory.create())
    .build();

You will also need to add the following dependency to your gradle file:

compile 'com.squareup.retrofit2:converter-gson:2.1.0'

Use the same version for the converter as you do for your retrofit. The above matches this retrofit dependency:

compile ('com.squareup.retrofit2:retrofit:2.1.0')

Also, note as of writing this, the retrofit docs are not completely updated, which is why that example got you into trouble. From the docs:

Note: This site is still in the process of being expanded for the new 2.0 APIs.

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