Android - the following class could not be found -

i creating bottom menu in android app

i have created on directory in res/menu/option_menu.xml this

<?xml version="1.0" encoding="utf-8"?> <menu xmlns:tools="http://schemas.android.com/tools"     xmlns:android="http://schemas.android.com/apk/res/android"     android:layout_width="wrap_content"     android:layout_height="wrap_content">      <item android:id="@+id/post_offer"         android:title="postoffer"         android:icon="@drawable/ic_launcher"         tools:ignore="hardcodedtext"         android:layout_width="wrap_content"         android:layout_height="wrap_content"/>      <item android:id="@+id/history"         android:title="history"         android:icon="@drawable/ic_launcher"         tools:ignore="hardcodedtext"         android:layout_width="wrap_content"         android:layout_height="wrap_content"/>      <item android:id="@+id/inbox"         android:title="inbox"         android:icon="@drawable/ic_launcher"         tools:ignore="hardcodedtext"         android:layout_width="wrap_content"         android:layout_height="wrap_content"/>      <item android:id="@+id/notifications"         android:title="notifications"         android:icon="@drawable/ic_launcher"         tools:ignore="hardcodedtext"         android:layout_width="wrap_content"         android:layout_height="wrap_content"/>      <item android:id="@+id/people"         android:title="people"         android:icon="@drawable/ic_launcher"         tools:ignore="hardcodedtext"         android:layout_width="wrap_content"         android:layout_height="wrap_content"/> </menu> 

then included xml in activity_main.xml , java

<include         layout="@menu/option_menu"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:layout_alignparentbottom="true" /> 

and java

@override     public boolean oncreateoptionsmenu(menu menu){         //menuinflater inflater = getmenuinflater();         //inflater.inflate(r.menu.option_menu, menu);         //return true;         getmenuinflater().inflate(r.menu.option_menu, menu);         return true;     }     @override     public boolean onoptionsitemselected(menuitem item){         switch (item.getitemid()){             case r.id.post_offer:                 startactivity(new intent(this, registeractivity.class));                 return true;             default:                 return super.onoptionsitemselected(item);         }      } 

now problem when try check activity_main.xml in design mode showing following error

missing classes

the following classes not found:

-item (fix build path, edit xml)

-menu(fix build path, edit xml)

edit

i using

compile sdk version: api 25:android 7.1.1(nougat)

build tool version: 25.0.1

then included xml in activity_main.xml , java

you shouldn't that. leave menu xml layout , inflate did in oncreateoptionsmenu(). should work.