java - How to get a String from HTTP and use it to build a JSON Object? -

i try string (a json file in reality) http server store data twitch stream.

the string got connecting : api.twitch.tv/kraken/streams/lainkk

i string in string variable , build json object string.

i wrote methods got systemerr in log while calling methods:

this own twitch api class :

package com.linkpulsion.bibix;  import android.util.log; import org.json.jsonobject; import java.io.bufferedreader; import java.io.inputstreamreader; import java.net.url; import java.net.urlconnection;  public class twitch {     private string channel;     public final static string twitch_api_server = "https://api.twitch.tv/kraken/";  /**  * constructor of java twitch api json generator  * @param channel cannel name infos  */ public twitch(string channel){     if(channel != null){         this.channel = channel;     } }  /**  * getter channel name  * @return string channel name  */ public string getchannel(){     return this.channel; }  protected string getjson(string mode){     string apiuri = twitch_api_server + mode + "/" + this.channel;     try{         url website = new url(apiuri);         urlconnection connection = website.openconnection();         bufferedreader in = new bufferedreader(new inputstreamreader(connection.getinputstream()));         stringbuilder response = new stringbuilder();         string inputline;         while ((inputline = in.readline()) != null)             response.append(inputline);         in.close();         return response.tostring();     }catch (exception e){         e.printstacktrace();         return null;     } }  protected jsonobject buildjson(string jsonraw){     jsonobject json = null;     try{         json = new jsonobject(jsonraw);     }catch (exception e){         e.printstacktrace();     }     return json; }  public void issreaming(){     string jsonraw = getjson("streams");     log.d(null,"retour " + jsonraw); } } 

thank !

i ran original code , got networkonmainthreadexception.

i made simple asynctask, , worked:

private class twitchasync extends asynctask<void, void, string> {     @override     protected string doinbackground(void... params) {         string str = twitch.getjson("streams");         return str;     }      @override     protected void onpostexecute(string result){         toast.maketext(mainactivity.this, "result: " + result, toast.length_long).show();          //testing buildjson:         jsonobject obj = twitch.buildjson(result);          log.d("json result: ",  obj.tostring());     } } 

here's full class used test with:

public class mainactivity extends appcompatactivity {      twitch twitch;     jsonobject jsonobj;  //instance variable can accessed anywhere in class code      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);         twitch = new twitch("aksynial");     }      @override     public boolean oncreateoptionsmenu(menu menu) {         getmenuinflater().inflate(r.menu.menu_main, menu);         return true;     }      @override     public boolean onoptionsitemselected(menuitem item) {          int id = item.getitemid();          if (id == r.id.action_settings) {              system.out.println("refreshing");             new twitchasync().execute();              return true;         }          return super.onoptionsitemselected(item);     }      private class twitchasync extends asynctask<void, void, string> {         @override         protected string doinbackground(void... params) {             string str = twitch.getjson("streams");             return str;         }          @override         protected void onpostexecute(string result){             toast.maketext(mainactivity.this, "result: " + result, toast.length_long).show();              //testing buildjson:             //assign instance variable jsonobj             jsonobj = twitch.buildjson(result);              log.d("json result: ",  jsonobj.tostring());         }     } } 

log result in onpostexecute():

 d/json result:﹕ {"_links":{"channel":"https:\/\/api.twitch.tv\/kraken\/channels\/aksynial","self":"https:\/\/api.twitch.tv\/kraken\/streams\/aksynial"},"stream":null}