mihon/app/src/main/res/menu/library.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto"
      xmlns:tools="http://schemas.android.com/tools"
      tools:context=".MainActivity">

    <item
        android:id="@+id/action_search"
        android:icon="@drawable/ic_search_white_24dp"
        android:title="@string/action_search"
        app:actionViewClass="android.support.v7.widget.SearchView"
        app:showAsAction="collapseActionView|ifRoom"/>

    <item
        android:id="@+id/action_filter"
        android:icon="@drawable/ic_filter_list_white_24dp"
        android:title="@string/action_filter"
        app:showAsAction="ifRoom">
        <menu>
            <item
                android:id="@+id/action_filter_downloaded"
                android:checkable="true"
                android:title="@string/action_filter_downloaded"/>
            <item
                android:id="@+id/action_filter_unread"
                android:checkable="true"
                android:title="@string/action_filter_unread"/>
            <item
                android:id="@+id/action_filter_empty"
                android:title="@string/action_filter_empty"/>
        </menu>
    </item>

    <item
        android:id="@+id/action_sort"
        android:icon="@drawable/ic_sort_white_24dp"
        android:title="@string/action_sort"
        app:showAsAction="never"
        >
        <menu>
            <group
                android:id="@+id/sort_group"
                android:checkableBehavior="single">
                <item
                    android:id="@+id/action_sort_alpha"
                    android:title="@string/action_sort_alpha"/>
                <item
                    android:id="@+id/action_sort_last_read"
                    android:title="@string/action_sort_last_read"/>
                <item
                    android:id="@+id/action_sort_last_updated"
                    android:title="@string/action_sort_last_updated"/>
            </group>
        </menu>
    </item>

    <item
        android:id="@+id/action_update_library"
        android:icon="@drawable/ic_refresh_white_24dp"
        android:title="@string/action_update_library"
        app:showAsAction="ifRoom"/>

    <item
        android:id="@+id/action_library_display_mode"
        android:title="@string/action_display_mode"
        app:showAsAction="never"/>

    <item
        android:id="@+id/action_edit_categories"
        android:title="@string/action_edit_categories"
        app:showAsAction="never"/>

</menu>