I have a problem in DatePicker on android I can't make it smaller than default size

This is the XML code which used:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
       <DatePicker
          android:id="@+id/datePicker1"
          android:layout_width="70dp"
          android:layout_height="40dp"
          android:layout_alignParentLeft="true"
          android:layout_below="@+id/addevent_location" />
</RelativeLayout>

Any help please