heart_beat.xml

<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:ordering="sequentially"
    android:interpolator="@android:interpolator/accelerate_decelerate">

    <set>
        <objectAnimator
            android:propertyName="scaleX"
            android:valueFrom="1.0"
            android:valueTo="0.8"
            android:duration="100" />
        <objectAnimator
            android:propertyName="scaleY"
            android:valueFrom="1.0"
            android:valueTo="0.8"
            android:duration="100" />
    </set>

    <set
        android:startOffset="1200">
        <objectAnimator
            android:propertyName="scaleX"
            android:valueFrom="0.8"
            android:valueTo="1.0"
            android:duration="100" />
        <objectAnimator
            android:propertyName="scaleY"
            android:valueFrom="0.8"
            android:valueTo="1.0"
            android:duration="100" />
    </set>

</set>