How to fix The following classes could not be instantiated in android -

i creating application consists of search widget on action bar downloaded here , had placed in layout.xml showing error on xml called

the following classes not instantiated:the following classes not instantiated: - com.milan.searchmenu.persistentsearch.searchbox (open class, show error log) see error log (window > show view) more details. tip: use view.isineditmode() in custom views skip code when shown in eclipse java.lang.nullpointerexception running application run time null pointer exception occurs can 1 tell me how fix this: activity:

 protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.manual);         actionbar actionbar;         actionbar = getactionbar();         search = (searchbox) findviewbyid(r.id.searchbox);         search.enablevoicerecognition(this);         for(int x = 0; x < 10; x++){             com.milan.searchmenu.persistentsearch.searchresult option = new searchresult("result " + integer.tostring(x), getresources().getdrawable(r.drawable.ic_history));             search.addsearchable(option);         }                search.setmenulistener(new menulistener(){              @override             public void onmenuclick() {                 //hamburger has been clicked                 toast.maketext(manual.this, "menu click", toast.length_long).show();                             }          });          search.setsearchlistener(new searchlistener() {              @override             public void onsearchtermchanged() {                 // todo auto-generated method stub              }              @override             public void onsearchopened() {                 // todo auto-generated method stub              }              @override             public void onsearchclosed() {                 // todo auto-generated method stub              }              @override             public void onsearchcleared() {                 // todo auto-generated method stub              }              @override             public void onsearch(string result) {                 toast.maketext(manual.this, result +" searched", toast.length_long).show();              }         }); 

this xml:

<relativelayout         android:id="@+id/relative_layout"         android:layout_width="wrap_content"         android:layout_height="51dp"         android:layout_alignparentleft="true"         android:layout_alignparentright="true"         android:layout_alignparenttop="true"          android:background="#673ab7">          <com.milan.searchmenu.persistentsearch.searchbox         android:layout_width="wrap_content"         android:id="@+id/searchbox"         android:layout_height="wrap_content">         </com.milan.searchmenu.persistentsearch.searchbox>     </relativelayout>      <android.support.v4.view.viewpager        android:id="@+id/pager"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_below="@+id/pager_sliding_tab_strip">     </android.support.v4.view.viewpager>     <com.milan.tabs.pagerslidingstrip.pagerslidingtabstrip        android:id="@+id/pager_sliding_tab_strip"        android:layout_width="match_parent"        android:layout_height="50dp"        android:layout_alignparentleft="true"        android:layout_below="@+id/relative_layout"        android:textsize="15dp"        app:pstsshouldexpand="true"        app:pstsdividercolor="#b39ddb"        app:pstsindicatorheight="45dp"         android:background="#673ab7"        app:pstsindicatorcolor="#ffffff">       </com.milan.tabs.pagerslidingstrip.pagerslidingtabstrip>        } 

you need add downloaded library dependency of module. in android studio following

1. place library in project somewhere.
2. right click on library , select "add library"
3. choose main module: either called app or mobile.
4. rebuild , should work