An example of the Android xml bundle format for creating an AnimatedVectorDrawable. See https://plus.google.com/+NickButcher/posts/A8KKxnJdg4r

avd_bundle.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  Copyright 2016 Google Inc.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
  -->

<animated-vector
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:aapt="http://schemas.android.com/aapt">

    <aapt:attr name="android:drawable">

        <vector
            android:width="24dp"
            android:height="24dp"
            android:viewportWidth="24"
            android:viewportHeight="24">

            <path
                android:name="root"
                android:strokeWidth="2"
                android:strokeLineCap="square"
                android:strokeColor="?android:colorControlNormal"
                android:pathData="M4.8,13.4 L9,17.6 M10.4,16.2 L19.6,7" />

        </vector>

    </aapt:attr>

    <target android:name="root">

        <aapt:attr name="android:animation">

            <objectAnimator
                android:propertyName="pathData"
                android:valueFrom="M4.8,13.4 L9,17.6 M10.4,16.2 L19.6,7"
                android:valueTo="M6.4,6.4 L17.6,17.6 M6.4,17.6 L17.6,6.4"
                android:duration="300"
                android:interpolator="@android:interpolator/fast_out_slow_in"
                android:valueType="pathType" />

        </aapt:attr>

    </target>

</animated-vector>

I'm still getting a "Attribute missing on Android namespace" for line Line 22 which if I resolve compounds to error at the line in the beginning - 1. requires api 21 2. animated-vector doen't have required attribute android:drawable
AS 2.2.2
Build tool 25.0.0
Gradle Plugin 2.2.2

Getting the same problem as nycodes9. Anyone find a solution to this?

Found a decent example of how to get this working: https://blog.stylingandroid.com/animatedvectordrawable-bundles/

There were some missing attributes in the provided example above.