In the res/drawable folder, put this:
progress.xml
<?xml version="1.0" encoding="utf-8"?>
<rotate xmlns:android="http://schemas.android.com/apk/res/android"
      android:pivotX="50%" 
      android:pivotY="50%" 
      android:fromDegrees="0"
      android:toDegrees="360">
    <shape 
        android:shape="ring" 
        android:innerRadiusRatio="3"
        android:thicknessRatio="8" 
        android:useLevel="false">
    <size 
        android:width="76dip" 
        android:height="76dip" />
    <gradient 
        android:type="sweep" 
        android:useLevel="false"
        android:startColor="#447a29" 
        android:endColor="#00ffffff"
        android:angle="0"/>
    </shape>
</rotate> 
Set startColor and endColor as per your choice .
Now set that progress.xml in ProgressBar's backgound .
Like this
<ProgressBar
  android:id="@+id/ProgressBar01" 
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:indeterminateDrawable="@drawable/progress"
 />