Android - imageview setBackground not applied after transition

Question

MainActivity.java

transition = new TransitionDrawable(new Drawable[]{
            new ColorDrawable(Color.TRANSPARENT),
            new BitmapDrawable(getResources(), BitmapFactory.decodeResource(getResources(), R.drawable.face1))
    });

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
        imageView.setBackground(ResourcesCompat.getDrawable(getResources(), R.drawable.default_image, null));
    }

    imageView.setImageDrawable(transition);
    transition.startTransition(3000);

    new Handler().postDelayed(new Runnable() {
        @Override
        public void run() {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
                imageView.setBackground(ResourcesCompat.getDrawable(getResources(), R.drawable.iv1_selector, null));
                Log.d("LOG", "CALLED");
            }
        }
    }, 3000);

iv1_selector.xml

<selector xmlns:android="http://schemas.android.com/apk/res/android"
android:enterFadeDuration="@android:integer/config_shortAnimTime"
android:exitFadeDuration="@android:integer/config_mediumAnimTime">

<item android:drawable="@drawable/iv_focused_drawable" android:state_focused="true" />
<item android:drawable="@drawable/iv_not_focused_drawable" android:state_focused="false" />

</selector>

I give a small animation, transition, to the imageView. After finishing the animation, imageView's background should be changed with a selector drawable inside a handler. However, for some reasons, its background is not applied, but when I click the imageView, it is applied. I have no idea on what's going on inside the handler. Any advice for this case?

This is how it looks like when the transition finished

But as you see this, I want to make it have the border around it. I don't understand why its background is not applied in the handler