I'm looking to create something such as button below :
I know how to create it like this but I want it with gradient border color.
Try This:
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item>
<!-- create gradient you want to use with the angle you want to use -->
<shape android:shape="rectangle">
<gradient
android:angle="0"
android:centerColor="@android:color/holo_blue_bright"
android:endColor="@android:color/holo_red_light"
android:startColor="@android:color/holo_green_light" />
<corners android:radius="@dimen/dp_10"/>
</shape>
</item>
<!-- create the stroke for top, left, bottom and right with the dp you want -->
<item
android:bottom="2dp"
android:left="2dp"
android:right="2dp"
android:top="2dp">
<shape android:shape="rectangle" >
<!-- fill the inside in the color you want (could also be a gradient again if you want to, just change solid to gradient and enter angle, start, maybe center, and end color) -->
<solid android:color="#fff" />
<corners android:radius="@dimen/dp_10"/>
</shape>
</item>
</layer-list>
chose the color you want..