Implementing custom Edittext style in android

I am creating custom edit text in android by adding xml in drawable res.it is as following

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://ift.tt/nIICcg" >
    <!-- Border -->
    <item>
        <shape>
            <solid android:color="@color/gray"></solid>
        </shape>
    </item>
    <!-- Body -->
    <item 
          android:bottom="1dp"
          android:right="0dp"
          android:left="0dp"
          android:top="0dp">
        <shape>
            <solid android:color="@color/white"></solid>
        </shape> 
    </item>
</layer-list>


 <EditText
                android:id="@+id/edt_password"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_gravity="center"
                android:background="@drawable/edittext"
                android:digits="1234567890"
                android:ellipsize="end"
                android:focusableInTouchMode="true"
                android:inputType="numberPassword"
                android:singleLine="true"
                android:textColor="@color/dark" />

so i just want edittext as a single line. But when i implement this, for few seconds the upper border of edittext is visible and then it goes away... I am really not getting why this is happening...