Visual examples help with this kind of question.

Boilerplate

In order to create a gradient, you create an xml file in res/drawable. I am calling mine my_gradient_drawable.xml:

<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="http://schemas.android.com/apk/res/android">    <gradient        android:type="linear"        android:angle="0"        android:startColor="#f6ee19"        android:endColor="#115ede" /></shape>

You set it to the background of some view. For example:

<View    android:layout_width="200dp"    android:layout_height="100dp"    android:background="@drawable/my_gradient_drawable"/>

type="linear"

Set the angle for a linear type. It must be a multiple of 45 degrees.

<gradient    android:type="linear"    android:angle="0"    android:startColor="#f6ee19"    android:endColor="#115ede" />

type="radial"

Set the gradientRadius for a radial type. Using %p means it is a percentage of the smallest dimension of the parent.

<gradient    android:type="radial"    android:gradientRadius="10%p"    android:startColor="#f6ee19"    android:endColor="#115ede" />

type="sweep"

I don't know why anyone would use a sweep, but I am including it for completeness. I couldn't figure out how to change the angle, so I am only including one image.

<gradient    android:type="sweep"    android:startColor="#f6ee19"    android:endColor="#115ede" />

center

You can also change the center of the sweep or radial types. The values are fractions of the width and height. You can also use %p notation.

android:centerX="0.2"android:centerY="0.7"

Try with this :

<?xml version="1.0" encoding="UTF-8"?><shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle" >    <gradient        android:angle="90"        android:centerColor="#555994"        android:endColor="#b5b6d2"        android:startColor="#555994"        android:type="linear" />    <corners         android:radius="0dp"/></shape>

You can create this 'half-gradient' look by using an xml Layer-List to combine the top and bottom 'bands' into one file. Each band is an xml shape.

See this previous answer on SO for a detailed tutorial: Multi-gradient shapes.