parsing data from JSON using Volley in Android

问题:

I tried parsing JSON data from "https://api.instagram.com/v1/media/popular?client_id=" + clientId; or any other url, in a tons of different ways! Used couple of JSONParsers, tutorials, readers .. everything, but still can't to get anything from those urls. Now I am using Volley library and still can't get it to work, here is my code and everything you need, if anyone has any ideas , please share them.

public  void LoadPictures()   {
    mRequestQueue =  Volley.newRequestQueue(this);
    mRequestQueue.add(new JsonObjectRequest(urlInst, null,
            new Listener<JSONObject>() {
                @Override
                public void onResponse(JSONObject response) {
                    try {
                        parseJSON(response);
                    } catch (JSONException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
            }, new ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            error.printStackTrace();
        }
    }));

this is my parseJSON method:

 private  void parseJSON(JSONObject json) throws JSONException{      
     // JSONObject value = json.getJSONObject("value");
 JSONArray items = json.getJSONArray("data");
 for(int i=0;i<items.length();i++) {
     JSONObject c=(JSONObject) items.get(i);
         JSONObject user = c.getJSONObject("user");
     String name= user.getString("username");
     JSONObject img=c.getJSONObject("images");
         JSONObject thum=img.getJSONObject("thumbnail");
         String urlOfPic = thum.getString("url");  
         PhotoInst photoData=new PhotoInst (i, urlOfPic, name);
         photos.add(photoData);
     }

this is JSON data I was supposed to get :

 "data": [{
    "type": "image",
    "users_in_photo": [],
    "filter": "Gotham",
    "tags": [],
    "comments": { ... },
    "caption": {
        "created_time": "1296656006",
        "text": "ãã¼ãâ¥ã¢ããªå§ãã¦ä½¿ã£ã¦ã¿ãã(^^)",
        "from": {
            "username": "cocomiin",
            "full_name": "",
            "type": "user",
            "id": "1127272"
        },
        "id": "26329105"
    },
    "likes": {
        "count": 35,
        "data": [{
            "username": "mikeyk",
            "full_name": "Kevin S",
            "id": "4",
            "profile_picture": "..."
        }, {...subset of likers...}]
    },
    "link": "http://instagr.am/p/BV5v_/",
    "user": {
        "username": "cocomiin",
        "full_name": "Cocomiin",
        "profile_picture": "http://distillery.s3.amazonaws.com/profiles/profile_1127272_75sq_1296145633.jpg",
        "id": "1127272"
    },
    "created_time": "1296655883",
    "images": {
        "low_resolution": {
            "url": "http://distillery.s3.amazonaws.com/media/2011/02/01/34d027f155204a1f98dde38649a752ad_6.jpg",
            "width": 306,
            "height": 306
        },
        "thumbnail": {
            "url": "http://distillery.s3.amazonaws.com/media/2011/02/01/34d027f155204a1f98dde38649a752ad_5.jpg",
            "width": 150,
            "height": 150
        },
        "standard_resolution": {
            "url": "http://distillery.s3.amazonaws.com/media/2011/02/01/34d027f155204a1f98dde38649a752ad_7.jpg",
            "width": 612,
            "height": 612
        }
    },
    "id": "22518783",
    "location": null
},

when I try putting random Toasts to see where is the problem, I can see the onResponse in my method LoadPictures isn't called at all? Where am I failing ? am I just overseeing something small or something else?

回答1:

@Mate - As visible from your json, you are getting a JsonArray i.e. "data". Hence, change your Listener to Listener<JSONArray> whihc ensures that it returns a JSONArray object. As a result your onResponse will now become,

@Override
public void onResponse(JSONArray response) {
try {
         parseJSON(response);
    } catch (JSONException e) {
         // TODO Auto-generated catch block
         e.printStackTrace();
    }
}

Let me know if this works.

回答2:

A few things you should verify first:

Are you sure you have the following in your manifest?

<uses-permission android:name="android.permission.INTERNET" />

Instagram requires some sort of API Key / authentication. Are you sure you are providing this?

Is your ErrorListener printing a stack trace? If it is, can you provide it?

That is where I would start.

回答3:

may this help you response = response.substring(5); makes to remove first 5 characters like data: and continue with JSONArray jsonArray = new JSONArray(response);