Анимация AnimatedVectorDrawable не запускается

Я пытаюсь создать простую игру, чтобы приостановить и отменить анимацию при нажатии, используя AnimatedVectorDrawable. Почему-то анимация не запускается.

Мой код выглядит следующим образом:

MainActivity.java

public class MainActivity extends AppCompatActivity {

private static final String TAG = "MainActivity";

private ImageView playPauseImgVw;
private AnimatedVectorDrawable playToPauseAvDrwble;
private AnimatedVectorDrawable pauseToPlayAvDrwble;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    playPauseImgVw = (ImageView) findViewById(R.id.activity_main_play_pause_btn_imgVw_id);
    playToPauseAvDrwble = (AnimatedVectorDrawable) getDrawable(R.drawable.animated_vector_play_to_pause);
    pauseToPlayAvDrwble = (AnimatedVectorDrawable) getDrawable(R.drawable.animated_vector_pause_to_play);

    playPauseImgVw.setImageDrawable(playToPauseAvDrwble);
    playPauseImgVw.setOnClickListener(newOnClickListener());
}

private View.OnClickListener newOnClickListener() {
    return new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            morph();
        }
    };
}

public void morph() {

    Log.d(TAG, "start animation");
    playToPauseAvDrwble.start();
}
}

transition_pause_to_play.xml

<set xmlns:android="http://schemas.android.com/apk/res/android">
<objectAnimator android:duration="1000"
    android:propertyName="pathData"
    android:valueFrom="@string/path_pause_button"
    android:valueTo="@string/path_play_button"
    android:valueType="pathType"
    android:interpolator="@android:interpolator/fast_out_slow_in" />

</set>

transition_play_to_pause.xml

<set xmlns:android="http://schemas.android.com/apk/res/android">
<objectAnimator android:duration="1000"
    android:propertyName="pathData"
    android:valueFrom="@string/path_play_button"
    android:valueTo="@string/path_pause_button"
    android:valueType="pathType"
    android:interpolator="@android:interpolator/fast_out_slow_in" />

</set>

animated_vector_pause_to_play.xml

<animated-vector xmlns:android="http://schemas.android.com/apk/res/android"
android:drawable="@drawable/vector_pause_button">
<target
    android:animation="@animator/transition_pause_to_play"
    android:name="path_pause_button" />
</animated-vector>

animated_vector_play_to_pause.xml

<animated-vector xmlns:android="http://schemas.android.com/apk/res/android"
android:drawable="@drawable/vector_play_button">
<target
    android:animation="@animator/transition_play_to_pause"
    android:name="path_play_button" />

vector_pause_button.xml

<vector xmlns:android="http://schemas.android.com/apk/res/android"
android:width="128dp"
android:height="128dp"
android:viewportHeight="600"
android:viewportWidth="600">

<path
    android:name="path_name_pause_button"
    android:fillAlpha="1"
    android:fillColor="@color/color_pause_button"
    android:pathData="@string/path_pause_button"
    android:strokeColor="@color/color_stroke_pause_button" />

vector_play_button.xml

<vector xmlns:android="http://schemas.android.com/apk/res/android"
android:width="128dp"
android:height="128dp"
android:viewportHeight="600"
android:viewportWidth="600">

<path
    android:name="path_name_play_button"
    android:fillAlpha="1"
    android:fillColor="@color/color_play_button"
    android:pathData="@string/path_play_button"
    android:strokeColor="@color/color_stroke_play_button" />

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.merryapps.vectoranimationpoc.MainActivity">

<ImageView
    android:id="@+id/activity_main_play_pause_btn_imgVw_id"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:clickable="true"
    android:scaleType="fitCenter"
    android:layout_centerHorizontal="true"/>

strings.xml

<resources>
<string name="app_name">VectorAnimationPoc</string>
<string name="path_play_button">M300,70 l 0,-70 95,70 0,0  M300,70 l 95,0 -95,70 0,0 z</string>
<string name="path_pause_button">M365,140 l 30,0 0,-140, -30,0  M300,140 l 30,0 0,-140 -30,0 z</string>
</resources>

Я что-то упустил здесь?