您好我正在尝试开发一个应用程序，我需要一个特定城市的餐馆列表。我正在尝试使用Zomato API。从https://developers.zomato.com/documentation的文档中，我觉得/ geocode方法最适合我需要的东西。对此的示例响应如下所示 -
{"location": {
"entity_type": "",
"entity_id": 0,
"title": "Al Quoz",
"latitude": "25.1345620000",
"longitude": "55.2365110000",
"city_id": 51,
"city_name": "Dubai",
"country_id": 214,
"country_name": "UAE"
},
"popularity": {
"popularity": "2.02",
"nightlife_index": "0.00",
"nearby_res": [
"18274882",
"206670",
"18279664",
"18264893",
"208532",
"210411",
"207764",
"18279641",
"203695"
],
"top_cuisines": [
"Indian",
"Chinese",
"Middle Eastern",
"Pakistani",
"Arabian"
],
"popularity_res": "100",
"nightlife_res": "10",
"subzone": "Al Quoz",
"subzone_id": 51301,
"city": "Dubai"
},
"link": "https://www.zomato.com/dubai/al-quoz-restaurants?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1",
"nearby_restaurants": {
"1": {
"restaurant": {
"R": {
"res_id": 18274882
},
"apikey": "--",
"id": "18274882",
"name": "Ice Lab",
"url": "https://www.zomato.com/dubai/ice-lab-al-quoz?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1",
"location": {
"address": "Behind Al Quoz Pond Park, Meydan Road, Al Quoz, Dubai",
"locality": "Al Quoz",
"city": "Dubai",
"city_id": 51,
"latitude": "0.0000000000",
"longitude": "0.0000000000",
"zipcode": "",
"country_id": 214
},
"cuisines": "Ice Cream",
"average_cost_for_two": 85,
"price_range": 2,
"currency": "AED",
"offers": [],
"thumb": "https://b.zmtcdn.com/images/res_avatar_120_1x_new.png",
"user_rating": {
"aggregate_rating": "3.7",
"rating_text": "Very Good",
"rating_color": "5BA829",
"votes": "30"
},
"photos_url": "https://www.zomato.com/dubai/ice-lab-al-quoz/photos#tabtop?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1",
"menu_url": "https://www.zomato.com/dubai/ice-lab-al-quoz/menu#tabtop?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1",
"featured_image": "",
"has_online_delivery": 0,
"is_delivering_now": 0,
"deeplink": "zomato://r/18274882",
"events_url": "https://www.zomato.com/dubai/ice-lab-al-quoz/events#tabtop?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1"
}
},
"2": {
"restaurant": {
"R": {
"res_id": 206670
},
"apikey": "--",
"id": "206670",
"name": "Dubai Amaravathi",
"url": "https://www.zomato.com/dubai/dubai-amaravathi-al-quoz?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1",
"location": {
"address": "Behind Old Grand Mall, Al Quoz, Dubai",
"locality": "Al Quoz",
"city": "Dubai",
"city_id": 51,
"latitude": "25.1465708500",
"longitude": "55.2434410527",
"zipcode": "",
"country_id": 214
},
"cuisines": "Indian, North Indian, South Indian, Chinese",
"average_cost_for_two": 50,
"price_range": 2,
"currency": "AED",
"offers": [],
"thumb": "https://b.zmtcdn.com/data/pictures/0/206670/a6140b8b6205d23c5fa123c7faeb7857_res_featured_thumb.png",
"user_rating": {
"aggregate_rating": "3.2",
"rating_text": "Good",
"rating_color": "9ACD32",
"votes": "40"
},
"photos_url": "https://www.zomato.com/dubai/dubai-amaravathi-al-quoz/photos#tabtop?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1",
"menu_url": "https://www.zomato.com/dubai/dubai-amaravathi-al-quoz/menu#tabtop?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1",
"featured_image": "https://b.zmtcdn.com/data/pictures/0/206670/a6140b8b6205d23c5fa123c7faeb7857_featured_v2.png",
"has_online_delivery": 1,
"is_delivering_now": 1,
"deeplink": "zomato://r/206670",
"order_url": "https://www.zomato.com/dubai/dubai-amaravathi-al-quoz/order?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1",
"order_deeplink": "",
"events_url": "https://www.zomato.com/dubai/dubai-amaravathi-al-quoz/events#tabtop?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1"
}
}
}
}
}
我正在尝试为此创建一个Android Model类，以便使用GSON解析响应。我的目标是简单地将“餐馆”对象放入List中，以便我可以将它们提供给卡视图适配器。
目前这就是我的模型 -
public class RestaurantsZomato {
public LocationDetails location;
public Popularity popularity;
public String link;
public NearbyRestaurants nearby_restaurants;
public static class LocationDetails {
public String entity_type;
public int entity_id;
public String title;
public String latitude;
public String longitude;
public int city_id;
public String city_name;
public int country_id;
public String country_name;
}
public static class Popularity {
public String popularity;
public String nightlife_index;
public List<String> nearby_res;
public List<String> top_cuisines;
public String popularity_res;
public String nightlife_res;
public String subzone;
public int subzone_id;
public String city;
}
public static class NearbyRestaurants {
public RestaurantDetails restaurant;
}
public class RestaurantDetails {
public Rest R;
public String apikey;
public String id;
public String name;
public String url;
public LocationDetails location;
public String cuisines;
public String average_cost_for_two;
public String price_range;
public String currency;
public List<String> offers;
public String thumb;
public UserRating user_rating;
public String photos_url;
public String menu_url;
public String featured_image;
public String has_online_delivery;
public String is_delivering_now;
public String deeplink;
public String events_url;
public String all_reviews_count;
public String photo_count;
public String phone_numbers;
public LocationDetails getLocation(){
return location;
}
public static class LocationDetails {
public String address;
public String locality;
public String city;
public String latitude;
public String longitude;
public String zipcode;
public String country_id;
public String getAddress() {
return address;
}
}
public static class UserRating {
public static String aggregate_rating;
public String rating_text;
public String rating_color;
public String votes;
}
public static class Rest {
public float res_id;
}
}
在我的片段中，在Web服务之后，我正在解析它 -
Ion.getDefault(getActivity()).configure().setLogging(getString(R.string.app_name), Log.DEBUG);
Ion.with(getActivity())
.load("https://developers.zomato.com/api/v2.1/geocode?lat=25.12819&lon=55.22724")
.setHeader("user-key","my-user-key")
.asJsonObject()
.setCallback(new FutureCallback<JsonObject>() {
@Override
public void onCompleted(Exception e, JsonObject result) {
Log.d("FoodFragment", result.toString());
RestaurantsZomato r = (RestaurantsZomato) new Gson().fromJson(result.toString(), new TypeToken<RestaurantsZomato>(){}.getType());
JsonObject nearby_restaurants = result.get("nearby_restaurants").getAsJsonObject();
Log.d("RestDetails",nearby_restaurants.toString());
JsonObject rest = nearby_restaurants.get("1").getAsJsonObject();
Log.d("RestZomato", rest.toString());
JsonObject details = rest.get("restaurant").getAsJsonObject();
Log.d("RestZomato", details.toString());
RestaurantDetails ad = new Gson().fromJson(details, new TypeToken<RestaurantDetails>(){}.getType());
Set<Map.Entry<String, JsonElement>> objects = nearby_restaurants.entrySet();
for (Map.Entry<String, JsonElement> entry : objects) {
System.out.println(entry.getKey() + "/" + entry.getValue());
if (entry.getValue() != null) {
RestaurantDetails rd = new Gson().fromJson(entry.getValue(), RestaurantDetails.class);
Log.d("simpletest",rd.getLocation().getAddress());
sTrips.add(rd);
}
}
adapter = new RestaurantAdapter(sTrips);
recyclerView.setAdapter(adapter);
}
});
}
其中sTrips是RestaurantDetails类型的对象。我在行sTrips.add（rd）中得到一个异常，因为rd为null。但是我无法弄清楚我做错了什么。请帮忙！
堆栈跟踪如下：
FATAL EXCEPTION: main
java.lang.NullPointerException
at majorproject.amity.smarttourist.fragments.FoodFragment$2.onCompleted(FoodFragment.java:161)
at majorproject.amity.smarttourist.fragments.FoodFragment$2.onCompleted(FoodFragment.java:131)
at com.koushikdutta.async.future.SimpleFuture.handleCallbackUnlocked(SimpleFuture.java:107)
at com.koushikdutta.async.future.SimpleFuture.setComplete(SimpleFuture.java:141)
at com.koushikdutta.async.future.SimpleFuture.setComplete(SimpleFuture.java:128)
at com.koushikdutta.ion.IonRequestBuilder$1.run(IonRequestBuilder.java:246)
at com.koushikdutta.async.AsyncServer$RunnableWrapper.run(AsyncServer.java:57)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:176)
at android.app.ActivityThread.main(ActivityThread.java:5419)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1046)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:862)
at dalvik.system.NativeStart.main(Native Method)
更新 错误是行Log.d（“simpletest”，rd.getLocation（）。getAddress（））;
我调试了它，发现rd的值确实为null。 Here is an image showing the debug
答案 0 :(得分：2)
实际上，您正在读取"1"/"2"的值，而您希望在for循环中读取restaurant的值。检查答案。
JsonObject rest = nearby_restaurants.get("1").getAsJsonObject();
// Log.d("RestZomato", rest.toString());
JsonObject details = rest.get("restaurant").getAsJsonObject();
// Log.d("RestZomato", details.toString());
RestaurantDetails ad = new Gson().fromJson(details, new TypeToken<RestaurantDetails>() {}.getType());
Set<Map.Entry<String, JsonElement>> objects = nearby_restaurants.entrySet();
for (Map.Entry<String, JsonElement> entry : objects) {
System.out.println(entry.getKey() + "/" + entry.getValue());
//entry.getValue() is the value of key "1"
JsonObject ob=entry.getValue().getAsJsonObject();
//you was reading value of "1" while you are suppose to read value of "restaurant"
//get value from "restaurant" object
if (ob != null) {
//RestaurantDetails is created to read value of "restaurant"
String restaurant=ob.get("restaurant").getAsJsonObject().toString();
RestaurantDetails rd = new Gson().fromJson(restaurant, RestaurantDetails.class);
System.out.println("Name "+rd.name);
System.out.println(rd.getLocation().address);
}
}