youtube api - How to solve android.view.InflateException with class <unknown>? -

i using youtubebaseactivity recyclerview adapder.:

android.view.inflateexception: binary xml file line #19: binary xml file line #19: error inflating class <unknown>    @ android.view.layoutinflater.inflate(layoutinflater.java:539)    @ android.view.layoutinflater.inflate(layoutinflater.java:423) 

code

public class youtubevideoplayeractivity extends youtubebaseactivity implements youtubeplayer.oninitializedlistener {          private static final int recovery_request = 1;         private youtubeplayerview youtubeview;         string uri;         string title;         textview videotitle;         recyclerview recyclerview;         requestqueue requestqueue;         youtubevideoplayersreenadapter adapder;         list<videothumblinedata> videothumblinedatas = new arraylist<videothumblinedata>();         @override         protected void oncreate(bundle savedinstancestate) {             super.oncreate(savedinstancestate);             setcontentview(r.layout.activity_main);              intent intent = getintent();             uri = intent.getstringextra("uri");             title = intent.getstringextra("title");             youtubeview = (youtubeplayerview) findviewbyid(r.id.youtube_view);             videotitle = (textview)findviewbyid(r.id.videotitle);             videotitle.settext(title);             youtubeview.initialize(config.youtube_api_key, this);             recyclerview =(recyclerview)findviewbyid(r.id.player_list_recycler_view);             recyclerview.setlayoutmanager(new linearlayoutmanager(getapplicationcontext()));             requestqueue = volley.newrequestqueue(getapplicationcontext());              requestqueue.add(new jsonarrayrequest(json_string[position], new response.listener<jsonarray>() {                 @override                 public void onresponse(jsonarray response) {                     try {                         (int i=response.length()-1; i>= 0 ;i--){                             jsonobject data = (jsonobject) response.get(i);                             log.d("video :"," :"+response);                             string ids = data.getstring("id");                             string video_headings = data.getstring("video_heading");                             string video_ids = data.getstring("video_id");                             string video_duration = data.getstring("duration");                             videothumblinedatas.add(new videothumblinedata(ids,video_headings,video_ids,video_duration));                         }                         adapder =new youtubevideoplayersreenadapter(videothumblinedatas);                         recyclerview.setadapter(adapder);                         adapder.notifydatasetchanged();                     }catch (jsonexception e){                         e.printstacktrace();                     }                 }             }, new response.errorlistener() {                 @override                 public void onerrorresponse(volleyerror error) {                  }             }));         }     }   public class youtubevideoplayersreenadapter extends recyclerview.adapter<recyclerview.viewholder> {     private context mcontext;     private list<videothumblinedata> albumlist;      class relatedthumbnailholder extends recyclerview.viewholder {          public textview title,duration;         public youtubethumbnailview thumbnail;           public relatedthumbnailholder(view view) {             super(view);             title = (textview) view.findviewbyid(r.id.player_title);             thumbnail = (youtubethumbnailview) view.findviewbyid(r.id.player_thumbnail);             duration = (textview)view.findviewbyid(r.id.player_duration);         }       }     public youtubevideoplayersreenadapter(list<videothumblinedata> albumlist) {         this.albumlist = albumlist;     }      @override     public recyclerview.viewholder oncreateviewholder(viewgroup parent, int viewtype) {         view view = layoutinflater.from(parent.getcontext()).inflate(r.layout.youtubeplayer_listview, parent,false);         return new relatedthumbnailholder(view);     }      @override     public void onbindviewholder(recyclerview.viewholder holder, final int position) {         relatedthumbnailholder relatedthumbnailholder = (relatedthumbnailholder)holder;         relatedthumbnailholder.title.settext(albumlist.get(position).getvideo_heading());         relatedthumbnailholder.duration.settext(albumlist.get(position).getduration());         relatedthumbnailholder.thumbnail.initialize(config.youtube_api_key, new youtubethumbnailview.oninitializedlistener() {             @override             public void oninitializationsuccess(youtubethumbnailview youtubethumbnailview, youtubethumbnailloader youtubethumbnailloader) {                 youtubethumbnailloader.setvideo(albumlist.get(position).getvideo_id());             }             @override             public void oninitializationfailure(youtubethumbnailview youtubethumbnailview, youtubeinitializationresult youtubeinitializationresult) {              }         });         relatedthumbnailholder.thumbnail.setonclicklistener(new view.onclicklistener() {             @override             public void onclick(view view) {                 intent = new intent(mcontext, youtubevideoplayeractivity.class);                 i.putextra("uri",albumlist.get(position).getvideo_id());                 i.putextra("title",albumlist.get(position).getvideo_heading());                 view.getcontext().startactivity(i);             }         });         relatedthumbnailholder.title.setonclicklistener(new view.onclicklistener() {             @override             public void onclick(view view) {                 intent = new intent(mcontext, youtubevideoplayeractivity.class);                 i.putextra("uri",albumlist.get(position).getvideo_id());                 i.putextra("title",albumlist.get(position).getvideo_heading());                 view.getcontext().startactivity(i);             }         });     }      @override     public int getitemcount() {         return albumlist.size();     } } 

activity_main.xml file using youtubevideoplayeractivity xml file

error comes

inflater android.view.inflateexception class <unknown> 

<?xml version="1.0" encoding="utf-8"?> <relativelayout xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:tools="http://schemas.android.com/tools"     android:layout_width="match_parent"     android:layout_height="match_parent"     xmlns:app="http://schemas.android.com/apk/res-auto"     tools:context=".activity.youtubevideoplayeractivity">      <com.google.android.youtube.player.youtubeplayerview         android:id="@+id/youtube_view"         android:layout_width="match_parent"         android:layout_height="wrap_content"/>      <android.support.v7.widget.cardview         android:layout_width="match_parent"         android:id="@+id/cardview"         android:background="#ffffff"         android:layout_height="wrap_content"         android:layout_below="@+id/youtube_view"         android:layout_alignparentright="true"         android:layout_alignparentend="true">      <textview         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:text="title"         android:gravity="center"         android:id="@+id/videotitle"         android:layout_alignparentleft="true"         android:layout_alignparentstart="true" />      </android.support.v7.widget.cardview>     <android.support.v7.widget.recyclerview         android:id="@+id/player_list_recycler_view"         android:layout_width="match_parent"         android:overscrollmode="never"         app:layout_behavior="@string/appbar_scrolling_view_behavior"         android:layout_height="match_parent"         android:layout_below="@+id/cardview"         android:layout_alignparentleft="true"         android:layout_alignparentstart="true"         android:layout_margintop="41dp" />  </relativelayout>