XML : Android Button Border Color

I am making Android Button, using following XML.

The output on Preview of Design, shows as below.

However when I run on Device, Samsung Duos. It shows totally different.

How can I set border.

  <?xml version="1.0" encoding="utf-8"?>  <shape xmlns:android="http://schemas.android.com/apk/res/android"      android:shape="rectangle" >        <stroke          android:width="3dp"          android:color="#d78d79" />    </shape>    

I also get an error in XML, but its working fine. Nothing shown when I mouse hover on error.

Can any one help?