public void setAlphaAnimatorValue(final float value) {
            final float old = mAlphaFraction;
            mAlphaFraction = value;
            if (old != mAlphaFraction) {
                invalidateSelf();
            }
        }
Set value as a fraction from 0f to 1f.
android/modules/module_common/src/main/java/github/tornaco/android/thanos/widget/checkable/CheckableFlipDrawable.java