java - Android - RecyclerView onClick not work -

i try change background of imageview clicking them, isn't work. i've in viewholder

i

attempt invoke virtual method ..streamviewholder.getadapterposition() on null object erference

import java.util.list;  import de.caglar.aqua.r; import de.caglar.aqua.objects.streamobject; import de.caglar.aqua.views.circularimageview; import android.support.v7.widget.cardview; import android.support.v7.widget.recyclerview; import android.view.layoutinflater; import android.view.view; import android.view.viewgroup; import android.widget.imageview; import android.widget.textview; import android.widget.toast;  public class streamadapter extends recyclerview.adapter<streamadapter.streamviewholder> implements view.onclicklistener {      public static list<streamobject> streams;      public streamadapter(list<streamobject> s){         streams = s;     }      public static class streamviewholder extends recyclerview.viewholder {               cardview cardview;         public textview streamtitle;         public textview streamtext;         public textview streamdescription;         public circularimageview streamphoto;         public imageview streamlike;          public streamviewholder(view itemview) {             super(itemview);             cardview = (cardview) itemview.findviewbyid(r.id.stream_cardview);             streamtitle = (textview) itemview.findviewbyid(r.id.stream_title);             streamtext = (textview) itemview.findviewbyid(r.id.stream_text);             streamdescription = (textview) itemview.findviewbyid(r.id.stream_description);             streamphoto = (circularimageview) itemview.findviewbyid(r.id.stream_photo);             streamlike = (imageview) itemview.findviewbyid(r.id.stream_like);         }     }      @override     public int getitemcount() {         return streams.size();     }      @override     public void onbindviewholder(streamviewholder streamviewholder, int i) {         streamviewholder.streamtitle.settext(streams.get(i).title);         streamviewholder.streamtext.settext(streams.get(i).text);         streamviewholder.streamdescription.settext(streams.get(i).description);         streamviewholder.streamphoto.setbackground(streams.get(i).photo);         if(streams.get(i).isliked) {             streamviewholder.streamlike.setimageresource(r.drawable.ic_action_like_active);         } else {             streamviewholder.streamlike.setimageresource(r.drawable.ic_action_like);         }         streamviewholder.streamlike.setonclicklistener(this);     }      @override     public void onclick(view v) {         try {             if (v instanceof imageview) {                 streamviewholder holder = (streamviewholder) v.gettag();                 int position = holder.getadapterposition();                 if(streams.get(position).isliked) {                     streams.get(position).isliked = false;                     holder.streamlike.setimageresource(r.drawable.ic_action_like);                 } else {                     streams.get(position).isliked = true;                     holder.streamlike.setimageresource(r.drawable.ic_action_like_active);                 }             }         } catch (exception e) {             toast.maketext(v.getcontext(), e.getmessage().tostring(), toast.length_long).show();         }     }      @override     public streamviewholder oncreateviewholder(viewgroup viewgroup, int i) {         view v = layoutinflater.from(viewgroup.getcontext()).inflate(r.layout.cardview_stream, viewgroup, false);         streamviewholder pvh = new streamviewholder(v);         return pvh;     }      @override     public void onattachedtorecyclerview(recyclerview recyclerview) {         super.onattachedtorecyclerview(recyclerview);     } } 

put in onbindviewholder method

streamviewholder.streamlike.settag(streamviewholder)