How to remove lag when Rotate Animation repeats on Android?

You need to put the linear_interpolator on the set.

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android" 
    android:interpolator="@android:anim/linear_interpolator">
    <rotate
        android:duration="1800"
        android:fromDegrees="0"
        android:pivotX="50%"
        android:pivotY="50%"
        android:repeatCount="infinite"
        android:toDegrees="360"/>
</set>

I ended up the increasing the android:toDegrees to above 360 like 3600 according to needs. The rotation is smooth now.