How does Android modify the background image of Prograssbar?

Reference URL

The picture of the native Prograssbar is really too ugly, how to solve it?

Solution:
1 Define an attribute animation below the drawable

<?xml version="1.0" encoding="utf-8"?><animated-rotate xmlns:android="http://schemas.android.com/apk/res/android"    android:drawable="@drawable/pb"    android:pivotX="50%"    android:pivotY="50%"    ></animated-rotate>

2 adding attributes to Prograssbar

 < ProgressBar  android:id  = "@+id/pb_left"  android:layout_width  = "wrap_content"             android:layout_height  = "wrap_content"  android:layout_gravity  = "center"  android:visibility  = "Gone"  android:indeterminatedrawable  =" @drawable/prograssbar_background_ Image " android:indeterminatebehavior  =" Repea T "/>   

Resolution: The figure is as follows:

Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced.

How does Android modify the background image of Prograssbar?