How change postion arc layout ?

[Mahmod Masoud]

<FrameLayout
    android:id="@+id/control_layout"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerInParent="true"
    android:layout_gravity="bottom|center_horizontal"
    android:background="@drawable/tab_bar_registration_selector" >

    <ImageView
        android:id="@+id/control_hint"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|center_horizontal" />
</FrameLayout>

this is my change on xml i want to make menu at buttom of layout but whan i run app there is still margin from buttom , How to solve this issue ?