Android UI-set the progressbar color

The basic principle is to create an XML file in the drawable directory to describe the background image. The content is as follows:
<? XML version = "1.0" encoding = "UTF-8"?>
<Layer-list xmlns: Android = "http://schemas.android.com/apk/res/android ">
<! -- Set background color image resources -->
<Item Android: Id = "@ Android: ID/background" Android: drawable = "@ drawable/BG"/>
<! -- Set level 2 progress bar color image resources -->
<Item Android: Id = "@ Android: ID/secondaryprogress" Android: drawable = "@ drawable/secondary"/>
<! -- Set level 1 progress bar color image resources -->
<Item Android: Id = "@ Android: ID/progress" Android: drawable = "@ drawable/progress"/>
16 </layer-List>
Then specify Android: progressdrawable attribute. The attribute value is the XML file just created.>