rotate wheel

<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:interpolator="@android:anim/accelerate_decelerate_interpolator"
    android:ordering="together" >

    <objectAnimator
        android:duration="1800"
        android:propertyName="rotation"
        android:repeatCount="infinite"
        android:repeatMode="restart"
        android:valueTo="-360"
        android:interpolator="@android:anim/linear_interpolator"
        android:valueType="floatType" />

</set>