ItemAnimator.java

import android.support.v4.view.ViewCompat;
import android.support.v4.view.ViewPropertyAnimatorCompat;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import com.mikepenz.itemanimators.DefaultAnimator;


public class ItemAnimator extends DefaultAnimator<ItemAnimator> {

    public boolean useAnimation = true;
    public int offset = 0;

    public void addAnimationPrepare(RecyclerView.ViewHolder holder) {
        if(useAnimation) {
            ViewCompat.setTranslationY(holder.itemView, holder.itemView.getHeight() * 0.4f);
            ViewCompat.setAlpha(holder.itemView, 0.0f);
        }
    }

    public ViewPropertyAnimatorCompat addAnimation(final RecyclerView.ViewHolder holder) {
        holder.itemView.setLayerType(View.LAYER_TYPE_HARDWARE, null);
        int off = holder.getAdapterPosition()-offset < 0 ? holder.getLayoutPosition() : holder.getAdapterPosition()-offset;
        return ViewCompat.animate(holder.itemView)
                .alpha(1)
                .translationY(0)
                .setDuration(useAnimation ? getAddDuration() + 30 * off : 0)
                .setInterpolator(getInterpolator())
                .setStartDelay(useAnimation ? (off) * 15L : 0);
    }

    public void addAnimationCleanup(RecyclerView.ViewHolder holder) {
        ViewCompat.setAlpha(holder.itemView, 1);
    }

    public ViewPropertyAnimatorCompat removeAnimation(final RecyclerView.ViewHolder holder) {
        holder.itemView.setLayerType(View.LAYER_TYPE_HARDWARE, null);
        return ViewCompat.animate(holder.itemView)
                .alpha(0)
                .setDuration(useAnimation ? getRemoveDuration() : 0)
                .setInterpolator(getInterpolator())
                .setStartDelay(0);
    }

    public void removeAnimationCleanup(RecyclerView.ViewHolder holder) {
        ViewCompat.setAlpha(holder.itemView, 1);
    }

    public ViewPropertyAnimatorCompat changeOldAnimation(RecyclerView.ViewHolder holder, ChangeInfo changeInfo) {
        return ViewCompat.animate(holder.itemView).setDuration(getChangeDuration()).alpha(0).translationX(changeInfo.toX - changeInfo.fromX).translationY(changeInfo.toY - changeInfo.fromY).setInterpolator(getInterpolator());
    }

    public ViewPropertyAnimatorCompat changeNewAnimation(RecyclerView.ViewHolder holder) {
        return ViewCompat.animate(holder.itemView).translationX(0).translationY(0).setDuration(getChangeDuration()).alpha(1).setInterpolator(getInterpolator());
    }

    public void changeAnimationCleanup(RecyclerView.ViewHolder holder) {
        ViewCompat.setAlpha(holder.itemView, 1);
    }
}

Thanks for this! Looks cute, especially with DecelerateInterpolator and 300 ms animation duration.
The class is called ItemAnimator, but gist called wrong — ItemAdapter.java.