Use below code to change background color of edit-text's border.
Create new XML file under drawable.
abc.xml
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<solid android:color="#00000000" />
<stroke android:width="1dip" android:color="#ffffff" />
</shape>
and add it as background of your edit-text
android:background="@drawable/abc"