AnimatedVectorDrawable 支持 < 24

Question

I have an animated vector drawable asset in my drawables folder. I use the following code to run it on button click

val myVectorDrawable = ResourcesCompat.getDrawable(
            resources,
            R.drawable.animation,
            theme
        )


        button.setOnClickListener {
            image.setImageDrawable(null)
            image.setImageDrawable(myVectorDrawable)

            val drawable = image.drawable

            if (drawable is AnimatedVectorDrawableCompat) {
                drawable.start()
            } else if (drawable is AnimatedVectorDrawable)
                drawable.start()

        }

This runs perfectly if the device runs an android version > 24 and crashes otherwise. I need to support android devices with minimum SDK 21.

My questions are

1. How to make my code support devices with 21 up to 24 .
2. is there a better way to run AnimatedVectorDrawable animation

Answer 1

If you know you are using an animated vector, you can use AnimatedVectorDrawableCompat.create() to create an AnimatedVectorDrawableCompat instance that is available on all API 14+ devices:

val drawable = AnimatedVectorDrawableCompat.create(
    this, // your Context
    R.drawable.animation)

button.setOnClickListener {
    image.setImageDrawable(null)
    image.setImageDrawable(drawable)

    drawable.start()
}

However, if you want a more generic approach, you must instead use AppCompatResources.getDrawable() instead of ResourcesCompat.getDrawable() as that properly takes into account the VectorDrawableCompat , AnimatedVectorDrawableCompat , and AnimatedStateListDrawableCompat classes in a way that is compatible with all API levels:

val drawable = AppCompatResources.getDrawable(
    this, // your Context
    R.drawable.animation)

button.setOnClickListener {
    image.setImageDrawable(null)
    image.setImageDrawable(drawable)

    if (drawable is Animatable) {
        drawable.start()
    }
}

Answer 2

Did you configure your build to use the support library implementation?

https://developer.android.com/guide/topics/graphics/vector-drawable-resources#vector-drawables-backward-solution

 android { defaultConfig { vectorDrawables.useSupportLibrary = true } }

Without this, the build system will create fallback (non-vector) resources for lower SDK versions instead of using the support implementation.