android - 如何使用 Retrofit 从异步回调中返回 String 或 JSONObject？

Question

例如调用

api.getUserName(userId, new Callback<String>() {...});

原因:

retrofit.RetrofitError: retrofit.converter.ConversionException:
com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: 
Expected a string but was BEGIN_OBJECT at line 1 column 2

我想我必须禁用 gson 解析为 POJO，但不知道该怎么做。

Answer 1

我想通了。很尴尬但是很简单……临时解决办法可能是这样的:

 public void success(Response response, Response ignored) {
            TypedInput body = response.getBody();
            try {
                BufferedReader reader = new BufferedReader(new InputStreamReader(body.in()));
                StringBuilder out = new StringBuilder();
                String newLine = System.getProperty("line.separator");
                String line;
                while ((line = reader.readLine()) != null) {
                    out.append(line);
                    out.append(newLine);
                }

                // Prints the correct String representation of body. 
                System.out.println(out);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

但是如果你想直接回调更好的方法是使用Converter .

public class Main {
public interface ApiService {
    @GET("/api/")
    public void getJson(Callback<String> callback);
}

public static void main(String[] args) {
    RestAdapter restAdapter = new RestAdapter.Builder()
            .setClient(new MockClient())
            .setConverter(new StringConverter())
            .setEndpoint("http://www.example.com").build();

    ApiService service = restAdapter.create(ApiService.class);
    service.getJson(new Callback<String>() {
        @Override
        public void success(String str, Response ignored) {
            // Prints the correct String representation of body.
            System.out.println(str);
        }

        @Override
        public void failure(RetrofitError retrofitError) {
            System.out.println("Failure, retrofitError" + retrofitError);
        }
    });
}

static class StringConverter implements Converter {

    @Override
    public Object fromBody(TypedInput typedInput, Type type) throws ConversionException {
        String text = null;
        try {
            text = fromStream(typedInput.in());
        } catch (IOException ignored) {/*NOP*/ }

        return text;
    }

    @Override
    public TypedOutput toBody(Object o) {
        return null;
    }

    public static String fromStream(InputStream in) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        StringBuilder out = new StringBuilder();
        String newLine = System.getProperty("line.separator");
        String line;
        while ((line = reader.readLine()) != null) {
            out.append(line);
            out.append(newLine);
        }
        return out.toString();
    }
}

public static class MockClient implements Client {
    @Override
    public Response execute(Request request) throws IOException {
        URI uri = URI.create(request.getUrl());
        String responseString = "";

        if (uri.getPath().equals("/api/")) {
            responseString = "{result:\"ok\"}";
        } else {
            responseString = "{result:\"error\"}";
        }

        return new Response(request.getUrl(), 200, "nothing", Collections.EMPTY_LIST,
                new TypedByteArray("application/json", responseString.getBytes()));
    }
  }
}

如果您知道如何改进此代码 - 请随时撰写。