IssueTracker

Steps to reproduce bug :

1. create a simple ValueAnimator XML

<?xml version="1.0" encoding="utf-8"?>
<animator xmlns:android="http://schemas.android.com/apk/res/android" android:valueType="intType" android:duration="500">
    <propertyValuesHolder android:valueFrom="0" android:valueTo="400" android:valueType="intType"/>
    <propertyValuesHolder android:valueFrom="400" android:valueTo="200" android:valueType="intType"/>
    <propertyValuesHolder android:valueFrom="200" android:valueTo="300" android:valueType="intType"/>
    <propertyValuesHolder android:valueFrom="300" android:valueTo="0" android:valueType="intType"/>
</animator>

2. use AnimatorInflaterCompat.loadAnimator to create ValueAnimator

3. run the app in any api < 24

Result :

The app will crashed due to java.lang.ClassCastException: android.animation.ValueAnimator cannot be cast to android.animation.ObjectAnimator

I have attached the full detail below.

As what caused this error, it occurs in AnimatorInfalterCompat

// AnimatorInfalterCompat.java
private static ValueAnimator loadAnimator(Context context, Resources res, Theme theme,
            AttributeSet attrs, ValueAnimator anim, float pathErrorScale, XmlPullParser parser)
            throws NotFoundException {
        TypedArray arrayAnimator = TypedArrayUtils.obtainAttributes(res, theme, attrs,
                AndroidResources.STYLEABLE_ANIMATOR);

        // CREATING arrayObjectAnimator, will always not-null
        TypedArray arrayObjectAnimator = TypedArrayUtils.obtainAttributes(res, theme, attrs,
                AndroidResources.STYLEABLE_PROPERTY_ANIMATOR);

        if (anim == null) {
            anim = new ValueAnimator();
        }

        parseAnimatorFromTypeArray(anim, arrayAnimator, arrayObjectAnimator, pathErrorScale,
                parser);
        // ....
}

In this function, before it pass TypedArray arrayObjectAnimator into parseAnimatorFromTypeArray method, instead of creating arrayObjectAnimator directly, it should check if ValueAnimator anim is null, just like how AnimatorInflater does :

    if (anim != null) {
            if (theme != null) {
                arrayObjectAnimator = theme.obtainStyledAttributes(attrs,
                        R.styleable.PropertyAnimator, 0, 0);
            } else {
                arrayObjectAnimator = res.obtainAttributes(attrs, R.styleable.PropertyAnimator);
            }
            anim.appendChangingConfigurations(arrayObjectAnimator.getChangingConfigurations());
        }

So a possible fix is simply add a flag before passing arrayObjectAnimator into the function:

private static ValueAnimator loadAnimator(Context context, Resources res, Theme theme,
            AttributeSet attrs, ValueAnimator anim, float pathErrorScale, XmlPullParser parser)
            throws NotFoundException {
        TypedArray arrayAnimator = TypedArrayUtils.obtainAttributes(res, theme, attrs,
                AndroidResources.STYLEABLE_ANIMATOR);

        // arrayObjectAnimator = null
        TypedArray arrayObjectAnimator;

        if (anim == null) {
            anim = new ValueAnimator();
        } else {
            arrayObjectAnimator = TypedArrayUtils.obtainAttributes(res, theme, attrs,
                AndroidResources.STYLEABLE_PROPERTY_ANIMATOR);
        }

        parseAnimatorFromTypeArray(anim, arrayAnimator, arrayObjectAnimator, pathErrorScale,
                parser);
        // ....
}

============================================================================================

FATAL EXCEPTION
2022-09-11 19:40:01.058 4269-4269/com.jimmy.whalepainter E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.jimmy.whalepainter, PID: 4269
    java.lang.ClassCastException: android.animation.ValueAnimator cannot be cast to android.animation.ObjectAnimator
        at androidx.vectordrawable.graphics.drawable.AnimatorInflaterCompat.setupObjectAnimator(AnimatorInflaterCompat.java:390)
        at androidx.vectordrawable.graphics.drawable.AnimatorInflaterCompat.parseAnimatorFromTypeArray(AnimatorInflaterCompat.java:376)
        at androidx.vectordrawable.graphics.drawable.AnimatorInflaterCompat.loadAnimator(AnimatorInflaterCompat.java:899)
        at androidx.vectordrawable.graphics.drawable.AnimatorInflaterCompat.createAnimatorFromXml(AnimatorInflaterCompat.java:529)
        at androidx.vectordrawable.graphics.drawable.AnimatorInflaterCompat.createAnimatorFromXml(AnimatorInflaterCompat.java:501)
        at androidx.vectordrawable.graphics.drawable.AnimatorInflaterCompat.loadAnimator(AnimatorInflaterCompat.java:132)
        at androidx.vectordrawable.graphics.drawable.AnimatorInflaterCompat.loadAnimator(AnimatorInflaterCompat.java:119)
        at androidx.vectordrawable.graphics.drawable.AnimatorInflaterCompat.loadAnimator(AnimatorInflaterCompat.java:103)
        at com.jimmy.whalepainter.ui.fragments.propertyanimator.PropertyAnimatorShiftButtonFragment.onViewCreated$lambda-7$lambda-4(PropertyAnimatorShiftButtonFragment.kt:66)
        at com.jimmy.whalepainter.ui.fragments.propertyanimator.PropertyAnimatorShiftButtonFragment.$r8$lambda$HrLZAcsXglCVJl5gUTyoMv9Mirc(PropertyAnimatorShiftButtonFragment.kt)
        at com.jimmy.whalepainter.ui.fragments.propertyanimator.PropertyAnimatorShiftButtonFragment$$ExternalSyntheticLambda4.onClick(D8$$SyntheticClass)
        at android.view.View.performClick(View.java:4756)
        at android.view.View$PerformClick.run(View.java:19749)
        at android.os.Handler.handleCallback(Handler.java:739)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:135)
        at android.app.ActivityThread.main(ActivityThread.java:5221)
        at java.lang.reflect.Method.invoke(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:372)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)