android - can not access to progress bar in an other activity -

i have objects in layout video view,text view , on comes this:

<?xml version="1.0" encoding="utf-8"?> <android.support.v7.widget.cardview android:id="@+id/cardview_mypost" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginbottom="@dimen/activity_vertical_margin" app:cardcornerradius="@dimen/activity_vertical_margin" app:cardelevation="@dimen/activity_vertical_margin" xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto">   <relativelayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="wrap_content"    android:background="@color/web_withe_color"    android:animatelayoutchanges="@anim/anim_list"    android:padding="8dp" > <!-- thumbnail image --> <videoview     android:layout_width="200dp"     android:layout_height="200dp"     android:id="@+id/video_orw"     /> <textview     android:layout_width="fill_parent"     android:layout_height="wrap_content"     android:textsize="@dimen/worth"     android:id="@+id/txt_titr_videopost"     android:background="#ee8888"     android:layout_alignparenttop="true"     android:layout_alignparentleft="true"     android:layout_alignparentstart="true" /> <textview     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:textappearance="?android:attr/textappearancelarge"     android:text="large text"     android:id="@+id/txt_date_videopost"     android:layout_alignbaseline="@+id/txt_cunter_videopost"     android:layout_alignbottom="@+id/txt_cunter_videopost"     android:layout_alignparentleft="true"     android:layout_alignparentstart="true" /> <textview     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:textappearance="?android:attr/textappearancesmall"     android:text="small text"     android:id="@+id/txt_cunter_videopost"     android:textcolor="@color/bright_foreground_disabled_material_dark"     android:layout_centervertical="true"     android:layout_alignright="@+id/txt_date_videopost"     android:layout_alignend="@+id/txt_date_videopost" /> <mediacontroller     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:id="@+id/mediacontroller2"     android:layout_alignparentbottom="true"     android:layout_alignparentright="true"     android:layout_alignparentend="true"     android:visibility="gone" /> <progressbar     style="?android:attr/progressbarstylelarge"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:id="@+id/progressbar_load_video"     android:layout_centervertical="true"     android:layout_alignright="@+id/txt_titr_videopost"     android:layout_alignend="@+id/txt_titr_videopost" /> </relativelayout> 

this group of row in recyclerview, , code

 public studentviewholder(view v) {         super(v);          progress_video=new progressbar(context);         final progressdialog[] pdialog = new progressdialog[1];         final showmessage sm=new showmessage(context);          thumbnail = (videoview) itemview               .findviewbyid(r.id.video_orw);         titr = (textview) itemview.findviewbyid(r.id.txt_titr_videopost);         year = (textview) itemview.findviewbyid(r.id.txt_date_videopost);         fi = (textview) itemview.findviewbyid(r.id.txt_cunter_videopost);         progressbar=(progressbar) itemview.findviewbyid(r.id.progressbar1);         progress_video=(progressbar) v.findviewbyid(r.id.progressbar_video);          v.setonclicklistener(new onclicklistener() {              @override             public void onclick(view v) {                   sm.show();                   if(videogalery.mediacontrol==null)                 videogalery.mediacontrol=new mediacontroller(context);                   videogalery.mediacontrol.setanchorview(videogalery.videoview);                  videogalery.videoview.setmediacontroller(videogalery.mediacontrol);              int itemposition = dataadapterpostvideo.recyclervvew.getchildlayoutposition(v);                                    videogalery.videoview.setvideouri(uri.parse(dataadapterpostvideo.videolist.get(itemposition).getmedia_path()));                 videogalery.videoview.start();                 videogalery.videoview.seekto(500);                  videogalery.videoview.setonpreparedlistener(new mediaplayer.onpreparedlistener() {                     @override                     public void onprepared(mediaplayer mp) {                        mp.setonbufferingupdatelistener(new mediaplayer.onbufferingupdatelistener() {                            @override                            public void onbufferingupdate(mediaplayer mp, int percent) {                                if(percent==100)                                    sm.hide();                            }                        });                     }                 });             }         });     } 

except progreccess bar , mediacontroller. when want access these 2 elements null access error.

@override public void onbindviewholder(final recyclerview.viewholder holder, int position) {     if (holder instanceof studentviewholder ) {          galery video= videolist.get(position);           if(string.valueof(video.getmime_type()).contains("video")) {             ((studentviewholder) holder).titr.settext(string.valueof(video.gettitel()));             ((studentviewholder) holder).year.settext(string.valueof(video.getpublish_at()));             ((studentviewholder) holder).fi.settext(string.valueof(video.getid()));             ((studentviewholder) holder).thumbnail.setvideouri(uri.parse(video.getmedia_path()));             ((studentviewholder) holder).progress_video.setvisibility(view.visible);             ((studentviewholder) holder).thumbnail.setonpreparedlistener(new mediaplayer.onpreparedlistener() {                 @override                 public void onprepared(mediaplayer mp) {                     mp.setonbufferingupdatelistener(new mediaplayer.onbufferingupdatelistener() {                         @override                         public void onbufferingupdate(mediaplayer mp, int percent) {                             if(percent==100)                                 ((studentviewholder) holder).progress_video.setvisibility(view.gone);                         }                     });                 }             });             ((studentviewholder) holder).thumbnail.seekto(2000);             // log.i("hamed",string.valueof(video.getid()));         }        animate((studentviewholder) holder);      } else {         ((progressviewholder) holder).progressbar.setindeterminate(true);     } } 

pay attention these codes. after these codes run application below codes. don't have access progressbar , face below error.

while can solved closer @ code. answer little differently.

npes views come due reasons such as:

• the view trying find not present in layout.
• the view trying find has different id trying find.
• the view doesn't have id.