如何自定义实现 Retrofit2.Call<T>

Question

我正在使用 Retrofit2，我想重写它的 Call.enqueue 方法。

到目前为止我是这样做的：

自定义调用：

    public class CustomCall<T> implements Call<T> {

        private final Call<T> delegate;
        //..every method has delegate method invoked in it

API：

        @GET
        CustomCall<TKBaseResponse> testConnection(@Url String customUrl);

但我不断收到这些错误：

    Unable to create call adapter for CustomCall<....>

和

    Could not locate call adapter for CustomCall<....>

关于如何正确执行此操作的任何方法？提前致谢！

Answer 1

首先创建一个ServiceManager类——

public final class ServiceManager {

    private static ServiceManager sServiceManager;

    /**
     * Gets the instance of the web services implementation.
     *
     * @return the singleton instance.
     */
    public static ServiceManager get() {
        if (sServiceManager == null) {
            sServiceManager = new ServiceManager();
        }
        return sServiceManager;
    }

    /**
     * Creates the services for a given HTTP Url, useful when testing
     * through multiple endpoints and unit testing
     *
     * @param clazz the service class.
     * @param <T>   type of the service.
     * @return the created services implementation.
     */
    public <T> T createService(Class<T> clazz) {
        return createService(clazz, HttpUrl.parse(ServiceApiEndpoints.SERVICE_ENDPOINT));
    }

    /**
     * Creates the services for a given HTTP Url, useful when testing
     * through multiple endpoints and unit testing
     *
     * @param clazz   the service class.
     * @param httpUrl the endpoint
     * @param <T>     type of the service.
     * @return the created services implementation.
     */
    public <T> T createService(Class<T> clazz, HttpUrl httpUrl) {
        Retrofit retrofit = getRetrofit(httpUrl);
        return retrofit.create(clazz);
    }

    public <T> T createService(Class<T> clazz, Retrofit retrofit) {
        return retrofit.create(clazz);
    }

    private Retrofit getRetrofit(HttpUrl httpUrl) {
        return new Retrofit.Builder()
                .baseUrl(httpUrl)
                .client(createClient())
                .addConverterFactory(getConverter())
                .build();
    }

    public Retrofit getPlainRetrofit(HttpUrl httpUrl) {
        return new Retrofit.Builder()
                .baseUrl(httpUrl)
                .client(new OkHttpClient.Builder().build())
                .addConverterFactory(getConverter())
                .build();
    }

    private Converter.Factory getConverter() {
        return GsonConverterFactory.create();
    }


    private OkHttpClient createClient() {
        return new OkHttpClient.Builder().addInterceptor(new RequestInterceptor()).build();
    }

}

ServiceApiEndpoints 是一个包含服务端点的类。

final class ServiceApiEndpoints {

    public static final String SERVICE_ENDPOINT = "your_app_url";
}

创建接口APIService

public interface APIService {
 String GET_INFO = "get_info";

    @GET(GET_INFO)
    Call<ResInfo[]> getInfo();
}

创建 ResInfo 模型。

public class ResInfo {
    private static final String FIELD_CONTENT = "content";

    public String getContent() {
        return mContent;
    }

    public void setContent(final String content) {
        mContent = content;
    }


    @SerializedName(FIELD_CONTENT)
    private String mContent;

    public ResInfo(){

    }
}

调用请求。

    private Call<ResInfo[]> mGetInfoAPICall;

    APIService apiService=ServiceManager.get().createService(APIService.class);
    mGetInfoAPICall = apiService.getInfo();
    mGetInfoAPICall.enqueue(new Callback<ResInfo[]>() {
    @Override
    public void onResponse(Call<ResInfo[]> call, Response<ResInfo[]> response) {

    }

    @Override
    public void onFailure(Call<ResInfo[]> call, Throwable t) {

    }
});

Answer 2

我在下面发布一个示例来帮助您进行改造。

像这样创建您的资源 (MyResource.java)。

Call<TKBaseResponse> testConnection(@@Url String customUrl);

初始化改造

private Resource getRetrofitResource(){
   //Initialize retrofit.
   final Retrofit = .....//your code to initialize retrofit
   return retrofit.create(MyResource.class);
}

要实现调用入队（异步改造调用），您需要将资源响应和响应处理程序（您的自定义实现）传递到入队方法中。我正在旁边发布我的 ResponseHandler 实现。

public abstract class ResponseHandler<T> {

    private static final String TAG = ResponseHandler.class.getSimpleName();

    private static final String LINE_SEPARATOR = System.getProperty("line.separator");

    private final Context context;

    public ResponseHandler() {
        this(null);
    }

    public ResponseHandler(final Context context) {
        this.context = context;
    }


    public abstract void onResponse(final T response);

    public void onError(final ErrorResponse errorResponse) {
        if (context == null) {
            return;
        }
        Log.e(TAG, "An error occurred while invoking service. Error Code: " + errorResponse.getErrorCode() + LINE_SEPARATOR + "Message: " + errorResponse.getMessage() + LINE_SEPARATOR);
        final AlertDialog.Builder alertBuilder = new AlertDialog.Builder(context);
        alertBuilder.setCancelable(true);
        alertBuilder.setTitle(R.string.title_server_error_dialog);
        alertBuilder.setMessage(R.string.network_error_message);
        alertBuilder.setPositiveButton(R.string.text_ok, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(final DialogInterface dialog, final int which) {
                dialog.dismiss();
            }
        });
        alertBuilder.show();
    }

    public void onFailure(Throwable throwable) {
        if (context == null) {
            return;
        }
        Log.e(TAG, "An error occurred while invoking service", throwable);
        final AlertDialog.Builder alertBuilder = new AlertDialog.Builder(context);
        alertBuilder.setCancelable(true);
        alertBuilder.setTitle(R.string.title_network_error_dialog);
        alertBuilder.setMessage(R.string.network_error_message);
        alertBuilder.setPositiveButton(R.string.text_ok, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(final DialogInterface dialog, final int which) {
                dialog.dismiss();
            }
        });
        alertBuilder.show();
    }

}

创建方法句柄响应。

protected <T> void handleResponse(Call<T> call, final ResponseHandler<T> responseHandler) {
        call.enqueue(new Callback<T>() {
            @Override
            public void onResponse(final Call<T> call, final Response<T> response) {
               if (response.isSuccess()) {
                if (responseHandler != null ) {
                    responseHandler.onResponse(response.body());
                }
            } else {
                final ErrorResponse errorResponse = parseError(response);
                if (responseHandler != null) {
                    responseHandler.onError(errorResponse);
                }
            }
            }

            @Override
            public void onFailure(final Call<T> call, final Throwable throwable) {
               if (responseHandler != null) {
                responseHandler.onFailure(throwable);
            }
            }
        });
    }

如果您对此有任何疑问，请告诉我。

现在像下面这样调用你的资源。

final MyResource resource = getRetrofitResource();
final Call<TKBaseResponse> response = resource .testConnection("ANY_URL_OF_YOUR_CHOICE");
handleResponse(response, new ResponseHandler<TKBaseResponse>(){

 public void onResponse(final TKBaseResponse response){
      //Do whatever you want to do here..
 }
    });