Quelle  typing_indicator.xml

<?xml version="1.0" encoding="utf-8"?>
<animated-vector xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:aapt="http://schemas.android.com/aapt"
    android:repeatMode="restart">

    <aapt:attr name="android:drawable">
        <vector
            android:name="typing_dots"
            android:width="24dp"
            android:height="24dp"
            android:viewportHeight="100"
            android:viewportWidth="100">
            <group android:name="dot0">
                <path
                    android:name="dot0_path"
                    android:fillAlpha="0.0"
                    android:fillColor="#000000"
                    android:pathData="M20,50m-10,0a10,10 0,1 1,20 0a10,10 0,1 1,-20 0" />
            </group>
            <group android:name="dot1">
                <path
                    android:name="dot1_path"
                    android:fillAlpha="0.0"
                    android:fillColor="#000000"
                    android:pathData="M50,50m-10,0a10,10 0,1 1,20 0a10,10 0,1 1,-20 0" />
            </group>
            <group android:name="dot2">
                <path
                    android:name="dot2_path"
                    android:fillAlpha="0.0"
                    android:fillColor="#000000"
                    android:pathData="M80,50m-10,0a10,10 0,1 1,20 0a10,10 0,1 1,-20 0" />
            </group>
        </vector>
    </aapt:attr>

    <target android:name="dot0_path">
        <aapt:attr name="android:animation">
            <set android:ordering="sequentially">
                <objectAnimator
                    android:duration="100"
                    android:interpolator="@android:interpolator/linear"
                    android:propertyName="fillAlpha"
                    android:startOffset="0"
                    android:valueFrom="0f"
                    android:valueTo="0.5f" />
                <objectAnimator
                    android:duration="100"
                    android:interpolator="@android:interpolator/linear"
                    android:propertyName="fillAlpha"
                    android:startOffset="300"
                    android:valueFrom="0.5f"
                    android:valueTo="0f" />
            </set>
        </aapt:attr>
    </target>

    <target android:name="dot1_path">
        <aapt:attr name="android:animation">
            <set android:ordering="sequentially">
                <objectAnimator
                    android:duration="100"
                    android:interpolator="@android:interpolator/linear"
                    android:propertyName="fillAlpha"
                    android:startOffset="300"
                    android:valueFrom="0f"
                    android:valueTo="0.5f" />
                <objectAnimator
                    android:duration="100"
                    android:interpolator="@android:interpolator/linear"
                    android:propertyName="fillAlpha"
                    android:startOffset="300"
                    android:valueFrom="0.5f"
                    android:valueTo="0f" />
            </set>
        </aapt:attr>
    </target>

    <target android:name="dot2_path">
        <aapt:attr name="android:animation">
            <set android:ordering="sequentially">
                <objectAnimator
                    android:duration="100"
                    android:interpolator="@android:interpolator/linear"
                    android:propertyName="fillAlpha"
                    android:startOffset="600"
                    android:valueFrom="0f"
                    android:valueTo="0.5f" />
                <objectAnimator
                    android:duration="100"
                    android:interpolator="@android:interpolator/linear"
                    android:propertyName="fillAlpha"
                    android:startOffset="300"
                    android:valueFrom="0.5f"
                    android:valueTo="0f" />
            </set>
        </aapt:attr>
    </target>
</animated-vector>