Question

这是我的JSON的片段，它很长，在“菜单”部分后，它会回到“位置”并重新开始。我不知道为什么但是我循环并将其打印到我的logcat它将停在“菜单”部分的随机位置并抛出错误。我不明白如何访问整个菜单部分。

{
"locations": [{
    "Location": {
        "id": "1",
        "name": "Scott Express Cafe",
        "building": "PKI",
        "monday_hours": "8am-2:30pm",
        "tuesday_hours": "8am-2:30pm",
        "wednesday_hours": "8am-2:30pm",
        "thursday_hours": "8am-2:30pm",
        "friday_hours": "8am-2:30pm",
        "saturday_hours": "Closed",
        "sunday_hours": "Closed"
    },
    "Section": [{
        "id": "3",
        "location_id": "1",
        "name": "Snacks",
        "Location": {
            "id": "1",
            "name": "Scott Express Cafe",
            "building": "PKI",
            "monday_hours": "8am-2:30pm",
            "tuesday_hours": "8am-2:30pm",
            "wednesday_hours": "8am-2:30pm",
            "thursday_hours": "8am-2:30pm",
            "friday_hours": "8am-2:30pm",
            "saturday_hours": "Closed",
            "sunday_hours": "Closed"
        },
        "Menu": [{
            "id": "278",
            "location_id": "1",
            "item_name": "Pop-tarts",
            "price_small": "$1.00",
            "price_medium": "",
            "price_large": "",
            "special": false,
            "special_start": "",
            "special_end": "",
            "details": "",
            "section_id": "3"
        }, {
            "id": "279",
            "location_id": "1",
            "item_name": "Cereal Bar",
            "price_small": "$1.00",
            "price_medium": "",
            "price_large": "",
            "special": false,
            "special_start": "",
            "special_end": "",
            "details": "",
            "section_id": "3"
        },

以下是错误：

07-02 20:08:19.878: D/TAG_LOCATIONS(4597): },
07-02 20:08:19.878: D/TAG_LOCATIONS(4597): {
07-02 20:08:19.878: D/TAG_LOCATIONS(4597): "price_medium": "",
07-02 20:08:19.878: D/TAG_LOCATIONS(4597): "id": "295",
07-02 20:08:19.878: D/TAG_LOCATIONS(4597): "details": "",
07-02 20:08:19.878: D/TAG_LOCATIONS(4597): "price_large": "",
07-02 20:08:19.878: D/TAG_LOCATIONS(4597): "item_name": "Wheat Thins Toasted Chips",
07-02 20:08:19.878: D/TAG_LOCATIONS(4597): "special_end": "",
07-02 20:08:19.878: D/TAG_LOCATIONS(4597): "special_start": "",
07-02 20:08:19.878: D/TAG_LOCATIONS(4597): "section_id": "3",
07-02 20:08:19.878: D/TAG_LOCATIONS(4597): "special": false,
07-02 20:08:19.878: D/TAG_LOCATIONS(4597): "price_small": "$0.85",
07-02 20:08:19.878: D/TAG_LOCATIONS(4597): "location_id": "1"
07-02 20:08:19.878: D/TAG_LOCATIONS(4597): },
07-02 20:08:19.878: D/TAG_LOCATIONS(4597): {
07-02 20:08:19.878: D/TAG_LOCATIONS(4597): "pric
07-02 20:08:19.888: W/System.err(4597): org.json.JSONException: No value for id
07-02 20:08:19.908: W/System.err(4597):     at o   rg.json.JSONObject.get(JSONObject.java:354)        
07-02 20:08:19.908: W/System.err(4597):     at org.json.JSONObject.getString(JSONObject.java:510)
07-02 20:08:19.908: W/System.err(4597):     at com.example.androidtablayout.FoodMenuList.onCreate(FoodMenuList.java:87)
07-02 20:08:19.908: W/System.err(4597):     at android.app.Activity.performCreate(Activity.java:5104)
07-02 20:08:19.918: W/System.err(4597):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
07-02 20:08:19.918: W/System.err(4597):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
07-02 20:08:19.918: W/System.err(4597):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
07-02 20:08:19.918: W/System.err(4597):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
07-02 20:08:19.918: W/System.err(4597):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
07-02 20:08:19.928: W/System.err(4597):     at android.os.Handler.dispatchMessage(Handler.java:99)
07-02 20:08:19.939: W/System.err(4597):     at android.os.Looper.loop(Looper.java:137)
07-02 20:08:19.939: W/System.err(4597):     at android.app.ActivityThread.main(ActivityThread.java:5041)
07-02 20:08:19.948: W/System.err(4597):     at  java.lang.reflect.Method.invokeNative(Native Method)
07-02 20:08:19.948: W/System.err(4597):    at java.lang.reflect.Method.invoke(Method.java:511)
07-02 20:08:19.958: W/System.err(4597):   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
07-02 20:08:19.958: W/System.err(4597):   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
07-02 20:08:19.958: W/System.err(4597):   at dalvik.system.NativeStart.main(Native Method)

我的班级：

public class FoodMenuList extends Activity {

// url to make request for menus
private static String url =               "http://mavmate.atticdev.ist.unomaha.edu/api/v1/services/getMenus";

// JSON Node names
private static final String TAG_LOCATIONS = "locations"; 
private static final String TAG_LOCATION = "Location";
private static final String TAG_ID = "id";
private static final String TAG_NAME = "name";
private static final String TAG_BUILDING = "building";


// contacts JSONArray
JSONArray locations = null;


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

Bundle extras = getIntent().getExtras(); 
String locationIDThing = extras.getString("locationID");

 // Hashmap for textView
ArrayList<HashMap<String, String>> menuItemList = new ArrayList<HashMap<String, String>>();

// Creating JSON Parser instance
JSONParser jParser = new JSONParser();


// getting JSON string from URL
JSONObject json = jParser.getJSONFromUrl(url);

try {
    // Getting Array of locations
    locations = json.getJSONArray(TAG_LOCATIONS);

    // looping through All locations
    for(int i = 0; i < locations.length(); i++){
        JSONObject c = locations.getJSONObject(i);

      Log.d("TAG_LOCATIONS", locations.toString(i));

        // Storing each json item in variable
        String id = c.getString(TAG_ID);
        String name = c.getString(TAG_NAME);
        String Location = c.getString(TAG_BUILDING);
        String building = c.getString(TAG_LOCATION);


        // creating new HashMap
        HashMap<String, String> map = new HashMap<String, String>();

        // adding each child node to HashMap key => value
        map.put(TAG_ID, id);
        map.put(TAG_NAME, name);
        map.put(TAG_LOCATION, Location);
        map.put(TAG_BUILDING, building);
        //map.put(TAG_PHONE_MOBILE, mobile);

        // adding HashList to ArrayList
        menuItemList.add(map);
    }

    } catch (JSONException e) {
    e.printStackTrace();
}

Answer 1

不是手动解析JSON来获取数据，而是考虑使用GSON library从JSON反序列化Java对象。例如，以下内容将json字符串转换为Person对象。

Person p = gson.fromJson(jsonStr, Person.class)

Answer 2

我认为您正在寻找JSON中错误位置的“id” “id”存在于“Location”或“Section”的元素

中

但不是直接在“位置”的元素中，这是代码所在的位置。

编辑：

JSONObject json = jParser.getJSONFromUrl(url);
for (JSONObject jsonObj : json.getJSONArray("locations"))
  for(JSONObject jsonObj2 : jsonObj.getJSONArray("Section"))
     for(JSONObject jsonObj3 : jsonObj2.getJSONArray("Menu"))
       System.out.println(jsonObj3.get("id");

考虑使用“optXXX”功能而不是“getXXX”，例如optString（“ID）

循环遍历多个JSON数组

2 个答案: