android - Activity cant populate the recyclerView with json -

i write example app ny times api . when test json ,it's ok . in activity when receive json . can't populate recyclerview json . it's lucky recyclerview populate json , nothing . , when run app on emulator android monitor says :

11226-11226/com.nytimes.nytimes e/recyclerview: no adapter attached; skipping layout

this postlistactivity.java recyclerview populate json :

package com.nytimes.nytimes.activities;  import android.content.intent; import android.os.bundle; import android.support.v7.app.appcompatactivity; import android.support.v7.widget.linearlayoutmanager; import android.support.v7.widget.recyclerview; import android.support.v7.widget.toolbar; import android.widget.toast;  import com.android.volley.request; import com.android.volley.response; import com.android.volley.volleyerror; import com.android.volley.toolbox.jsonobjectrequest; import com.nytimes.nytimes.r; import com.nytimes.nytimes.adapters.postlistrecyclerviewadapter; import com.nytimes.nytimes.app.appcontroller; import com.nytimes.nytimes.pojos.postdata;  import org.json.jsonarray; import org.json.jsonexception; import org.json.jsonobject;  import java.util.arraylist; import java.util.list;   public class postlistactivity extends appcompatactivity {     recyclerview poslistrecyclerview;     private list<postdata> postdatalist = new arraylist<postdata>();      @override     public void oncreate(bundle savedinstancestate) {          super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_post_list);          setuptoolbar();          //=============== hit sendjsonresquest ===================//         sendjsonrequest();           //=============== initialize recyclerview ===================//         poslistrecyclerview = (recyclerview) findviewbyid(r.id.recyclerpostlist);         poslistrecyclerview.sethasfixedsize(true);         poslistrecyclerview.setlayoutmanager(new linearlayoutmanager(postlistactivity.this));      }      //===================  setuptoolbar =====================//     private void setuptoolbar() {         toolbar postlisttoolbar = (toolbar) findviewbyid(r.id.postlisttoolbar);         setsupportactionbar(postlisttoolbar);         getsupportactionbar().setdisplayshowtitleenabled(false);         getsupportactionbar().sethomeasupindicator(r.mipmap.ic_left);         getsupportactionbar().setdisplayhomeasupenabled(true);     }      //===================  send json request =====================//     private void sendjsonrequest() {          //getintent category         intent intentgetcategory = getintent();         string category = intentgetcategory.getextras().getstring("category");           //find specific url string format         string turl = string.format("http://api.nytimes.com/svc/topstories/v1/%s.json?api-key=626663e02b8fe9d8:7:74012032", category);         jsonobjectrequest request = new jsonobjectrequest(request.method.get, turl, (string) null, new response.listener<jsonobject>() {             @override             public void onresponse(jsonobject response) {                  //hit parsejsonresponse                 parsejsonresponse(response);                  //setadapter recyclerview                 poslistrecyclerview.setadapter(new postlistrecyclerviewadapter(postlistactivity.this, postdatalist));               }         }, new response.errorlistener() {             @override             public void onerrorresponse(volleyerror error) {                 toast.maketext(postlistactivity.this, "onerrorresponse volley error listener", toast.length_short).show();             }         });          //add request request queue         appcontroller.getinstance().addtorequestqueue(request);      }       //===================  parsejsonresponse =====================//     private void parsejsonresponse(jsonobject response) {         if (response != null) {              try {                 jsonarray results = response.getjsonarray("results");                  (int = 0; < results.length(); i++) {                      jsonobject currentresult = results.getjsonobject(i);                      postdata postdata = new postdata();                      postdata.setposttitle(currentresult.getstring("title"));                     postdata.setposturl(currentresult.getstring("url"));                      jsonarray multimedias = currentresult.getjsonarray("multimedia");                      (int m = 0; m < multimedias.length(); m++) {                         jsonobject thumbnail = multimedias.getjsonobject(0);                         postdata.setpostthumbnail(thumbnail.getstring("url"));                     }                     postdatalist.add(postdata);                 }              } catch (jsonexception e) {                 e.printstacktrace();             }           } else {             toast.maketext(postlistactivity.this, "response empty else parsejsonresponse", toast.length_short).show();         }     } } 

i think adapter isn't in place .

you initialize adapter first time when download json data , until recyclerview doesn't have adapter work with.

i suggest:

1) define adapter , data array @ class level (outside oncreate):

postlistrecyclerviewadapter adapter; arraylist<postdata> postdatalist; 

2) initialize empty adapter once in oncreate @ time of initializing recyclerview empty postdatalist.

    //=============== initialize recyclerview ===================//          poslistrecyclerview = (recyclerview) findviewbyid(r.id.recyclerpostlist);         poslistrecyclerview.sethasfixedsize(true);         poslistrecyclerview.setlayoutmanager(new linearlayoutmanager(postlistactivity.this));      //=============== initialize adapter, data array , set adapter ===================//            postdatalist = new arraylist<postdata>();          postlistrecyclerviewadapter adapter = new postlistrecyclerviewadapter(this, postdatalist)           poslistrecyclerview.setadapter(adapter); 

3) update postdatalist when download new data , insert in postdatalist

4) call notifydatasetchanged on adapter notify data has changed.

where setting adapter in onresponse, call following function after have inserted new data postdatalist.

adapter.notifydatasetchanged();