android - 如何捕捉对 get 方法 android 改造的响应？

Question

我是 android 开发的新手，正在尝试学习它。我最近遇到了一个问题，当我使用 get 方法时，我得到如下响应:

由于后端的status 为“0”，我无法捕获“response_data”数组。谁能指导我如何才能收到回复。谢谢。

API 客户端:

 public class ApiClient {
    private final static String BASE_URL = "http://api.xxxxxx.com/app/";
    public static ApiClient apiClient;
    private Retrofit retrofit = null;

    public static ApiClient getInstance() {
        if (apiClient == null) {
            apiClient = new ApiClient();
        }
        return apiClient;
    }
 public Retrofit getClient() {
        return getClient(null);
    }



    private Retrofit getClient(final Context context) {

        HttpLoggingInterceptor interceptor = new 
HttpLoggingInterceptor();
        interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
        OkHttpClient.Builder client = new OkHttpClient.Builder();
        client.readTimeout(60, TimeUnit.SECONDS);
        client.writeTimeout(60, TimeUnit.SECONDS);
        client.connectTimeout(60, TimeUnit.SECONDS);
        client.addInterceptor(interceptor);
        client.addInterceptor(new Interceptor() {
            @Override
            public okhttp3.Response intercept(Chain chain) throws 
IOException {
                Request request = chain.request();

                return chain.proceed(request);
            }
        });

        retrofit = new Retrofit.Builder()
                .baseUrl(BASE_URL)
                .client(client.build())
                .addConverterFactory(GsonConverterFactory.create())
                .build();


        return retrofit;
    }

    }

主要 Activity :

public class MainActivity extends AppCompatActivity {

TextView tvResponse;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    tvResponse=findViewById(R.id.tvResponse);

    ApiInterface apiInterface = ApiClient.getInstance().getClient().create(ApiInterface.class);
    Call<ResponseData> responseDataCall=apiInterface.getData();
    responseDataCall.enqueue(new Callback<ResponseData>() {
        @Override
        public void onResponse(Call<ResponseData> call, Response<ResponseData> response) {
            if (response.isSuccessful() && response.body()!=null && response!=null){
                List<ResponseDataItem> data=response.body().getResponseData();

            }
        }

        @Override
        public void onFailure(Call<ResponseData> call, Throwable t) {
            t.printStackTrace();
        }
    });
}

响应数据:

public class ResponseData {
@SerializedName("response_data")
private List<ResponseDataItem> responseData;

@SerializedName("status")
private int status;

public void setResponseData(List<ResponseDataItem> responseData){
    this.responseData = responseData;
}

public List<ResponseDataItem> getResponseData(){
    return responseData;
}

public void setStatus(int status){
    this.status = status;
}

public int getStatus(){
    return status;
}

Answer 1

在这种情况下，您需要让 Gson 知道您希望如何解析您的 json。您可以为每个特定的类案例添加许多特定的 TypeAdapter，或者您可以创建一个将用于解析所有 json 的 TypeAdapterFactory。请记住将其添加到您的 Retrofit 构建器中。

此代码示例是一个 TypeAdapterFactory，它将忽略 status 并仅解析 response_data 到您的对象。

class ResponseDataTypeAdapterFactory implements TypeAdapterFactory {

    public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
        TypeAdapter<T> delegate = gson.getDelegateAdapter(this, type);
        TypeAdapter<JsonElement> elementTypeAdapter = gson.getAdapter(JsonElement.class);

        return new TypeAdapter<T>() {
            public void write(JsonWriter out, T value) throws IOException {
                delegate.write(out, value);
            }

            public T read(JsonReader reader) throws IOException {

                JsonElement jsonElement = elementTypeAdapter.read(reader);

                if (jsonElement.isJsonObject()) {
                    JsonObject jsonObject = jsonElement.getAsJsonObject();
                    if (jsonObject.has("response_data")) {
                       jsonElement = jsonObject.get("response_data");
                    }
                }

                return delegate.fromJsonTree(jsonElement);
            }
        };
    }
}

在你的 Retrofit 构建器上

Gson gson = new GsonBuilder()
    .registerTypeAdapterFactory(ResponseDataTypeAdapterFactory())
    .create();

new Retrofit.Builder()
    .baseUrl(BASE_URL)
    .client(client.build())
    .addConverterFactory(new GsonConverterFactory.create(gson))
    .build();

而在Retrofit接口(interface)，只需要调用response_data映射对应的类即可。

public interface ApiInterface {

    @GET("/product-data")
    Call<List<ResponseDataItem>> fetchData();
}

通过此实现，您可以删除 ResponseData 类并只关心重要的模型。