Android Navigation Drawer Icon Problemi

activity_main_drawer.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">

    <group android:checkableBehavior="all">
        <item
            android:id="@+id/nav_login"
            android:icon="@drawable/login"
            android:layout_centerVertical="true"
            android:title="Giriş Yap"/>
        <item
            android:id="@+id/nav_gallery"
            android:icon="@drawable/ic_menu_gallery"
            android:title="Gallery"/>
        <item
            android:id="@+id/nav_slideshow"
            android:icon="@drawable/ic_menu_slideshow"
            android:title="Slideshow"/>
        <item
            android:id="@+id/nav_manage"
            android:icon="@drawable/ic_menu_manage"
            android:title="Tools"/>
    </group>

    <item android:title="Communicate">
        <menu>
            <item
                android:id="@+id/nav_share"
                android:icon="@drawable/buttona"
                android:title="Share"/>
            <item
                android:id="@+id/nav_send"
                android:icon="@drawable/ic_menu_send"
                android:title="Send"/>
        </menu>
    </item>

</menu>

Ek'te verdiğim gibi resim neden görünmüyor login iconu ?