how to set android.support.v7.widget.SearchView width size?

Hi

I am using android.support.v7.widget.SearchView in ActionBar as item. Below is my code. Its not occupying entire width. See the screenshot, i want to increase its width

 <item android:id="@+id/search"
       app:showAsAction="always"
       android:layout_width="wrap_content"
       app:actionViewClass="android.support.v7.widget.SearchView" />