xml drawable
create shape.xml in drawable folder
like shape.xml
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" >
<stroke android:width="2dp"
android:color="#FFFFFF"/>
<gradient
android:angle="225"
android:startColor="#DD2ECCFA"
android:endColor="#DD000000"/>
<corners
android:bottomLeftRadius="7dp"
android:bottomRightRadius="7dp"
android:topLeftRadius="7dp"
android:topRightRadius="7dp" />
</shape>
and in myactivity.xml
you can use
<Button
android:id="@+id/btn_Shap"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/Shape"
android:background="@drawable/shape"/>