Android : Cant set position on PagerTabStrip android

i have problem with PagerTabStrip and the problem comes when i want to posstion PagerTabStrip in the right bottom of ViewPager.This is my code

 <RelativeLayout
            android:id="@+id/listOfImage"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@id/searchResultDetailInfo" >

            <android.support.v4.view.ViewPager
                android:id="@+id/pager"
                android:layout_width="match_parent"
                android:layout_height="200dp"
                android:background="@android:color/darker_gray" >

                <android.support.v4.view.PagerTabStrip
                    android:id="@+id/pager_tab_strip"
                    android:layout_width="100dp"
                    android:layout_height="wrap_content"
                   -> My problem comes here i try to possition to right  and bottom
                     but cant when i set right it appear right and top when set bottom
                     appear bottom left....
                    android:layout_gravity="bottom"
                    android:background="@color/footerColor"

                    android:textColor="#fff" />
            </android.support.v4.view.ViewPager>


        </RelativeLayout>