Android : Auto resize an imageView

I have a Brick image and i am trying to create a 6x6 table of the imageView. i tried many ways to set the imageview to auto resize by the screen size but i didn't success. that is a part of my XML's code:

<RelativeLayout
    android:layout_width="fill_parent"
    android:layout_height="match_parent"
    android:layout_below="@+id/relativeLayout"
    android:paddingTop="10dp"
    android:paddingRight="10dp"
    android:paddingBottom="10dp"
    android:paddingLeft="10dp"
    android:gravity="center_vertical|center_horizontal">

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:weightSum="1">
    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/s_1"
        android:layout_marginRight="5dp"
        android:layout_marginBottom="5dp"
        android:layout_marginTop="5dp"
        android:layout_marginLeft="5dp"
        android:scaleType="fitXY"
        android:adjustViewBounds="true"
        android:src="@drawable/brick_clean" />


        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/s_2"
            android:layout_marginRight="5dp"
            android:layout_marginBottom="5dp"
            android:layout_marginTop="5dp"
            android:layout_marginLeft="5dp"
            android:scaleType="fitXY"
            android:adjustViewBounds="true"
            android:src="@drawable/brick_clean" />

        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/s_3"
            android:layout_marginRight="5dp"
            android:layout_marginBottom="5dp"
            android:layout_marginTop="5dp"
            android:layout_marginLeft="5dp"
            android:scaleType="fitXY"
            android:adjustViewBounds="true"
            android:src="@drawable/brick_clean" />



    </LinearLayout>


</RelativeLayout>

and that is my result:

what i want is all the imageViews will automatic resize to the same width and height and fill all the linearLayout. how will i do it?