android - How to work with pagination URL from Soundcloud API with Retrofit -

i'm using retrofit list of tracks soundcloud-api. request results in callback list of tracks - without pagination works. when add parameter pagination (linked_partitioning=1) request, retrofit returns error. cannot figure out how write callback-type url-string next page , list result.

retrofit call:

map<string, string> querymap = new hashmap<string, string>(); querymap.put("client_id" , my_config.client_id); querymap.put("tag", "loop" ); querymap.put("license", "cc-by-sa" );  querymap.put("limit", "10");   // causing  different return type ---> error querymap.put("linked_partitioning", "1" );   scservice = retrofitrestadapter.getservice(); scservice.searchtracks(querymap, callback); // callback function success  not reached because of error 

interface get-request:

@get("/tracks") public void searchtracks(@querymap map<string, string> filters, callback<list<my_track>> cb); 

retrofit callback:

callback<list<my_track>> callbacktracks = new callback<list<my_track>>() {     @override     public void success(list<my_track> tracks, response response) {...}     @override     public void failure(retrofiterror error) {...} }; 

retrofit exception:

com.google.gson.jsonsyntaxexception: java.lang.illegalstateexception: expected begin_array begin_object @ line 1 column 2 path $ 

edit: result pattern of soundcloud api:

without pagination result array/list of track-elements , looks this:

[{"download_url":null,"key_signature":"","user_favorite":false,...}, {...},{...}] 

with pagination result element containing collection plus next_href:

{"collection":[ {"download_url":null,"key_signature":"",...}, {...}, {...} ],"next_href":"https://..."}   

---

how need declare returntype of callback separate collection-array , "next_href" result ?

thanks!

from error provided, can guess, after requested pagination, api returns result in object not array. example, before using pagination, result like

[    {       item 1,       item 2    },    {       item 1,       item 2    }  ] 

and after using pagination, result like

{    page: 1,    count: 400,    results: [        {           item 1,           item 2        },         {           item 1,           item 2        }    ] } 

so may need change mapping pagination. (since not providing result pattern, think cause of error)

answer edit

currently mapping returning json list of my_track class. need make class mapping , declare list of my_track property. example:

public class mytrackholder {     public final string next_href;     public final list<my_track> collection;      public mytrackholder(final string next_href, final list<my_track> collection)     {         this.next_href = next_href;         this.collection = collection;     }  } 

and interface like

@get("/tracks") public void searchtracks(@querymap map<string, string> filters, callback<mytrackholder> cb); 

and call interface method follows

callback<mytrackholder> callbacktracks = new callback<mytrackholder>() {     @override     public void success(mytrackholder trackholder, response response) {...}     @override     public void failure(retrofiterror error) {...} }; 

you retrieve tracks using

list<my_track> tracks = trackholder.collection;