ExpandableItemViewHolder

ExpandableItemViewHolder.java

import android.animation.ValueAnimator;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.view.animation.LinearInterpolator;

public abstract class ExpandableItemViewHolder extends RecyclerView.ViewHolder {

    private int mOriginalHeight;
    private boolean mIsViewExpanded;

    public ExpandableItemViewHolder(View itemView) {
        super(itemView);
        itemView.setOnClickListener(mOnClickListener);
    }

    abstract int getExpandedHeight(int originalHeight);

    private final View.OnClickListener mOnClickListener = new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (mOriginalHeight == 0) {
                mOriginalHeight = itemView.getHeight();
            }
            ValueAnimator valueAnimator;
            if (!mIsViewExpanded) {
                mIsViewExpanded = true;
                valueAnimator = ValueAnimator.ofInt(mOriginalHeight, getExpandedHeight(mOriginalHeight));
            } else {
                mIsViewExpanded = false;
                valueAnimator = ValueAnimator.ofInt(getExpandedHeight(mOriginalHeight), mOriginalHeight);
            }
            valueAnimator.setDuration(300);
            valueAnimator.setInterpolator(new LinearInterpolator());
            valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
                public void onAnimationUpdate(ValueAnimator animation) {
                    itemView.getLayoutParams().height = (Integer) animation.getAnimatedValue();
                    itemView.requestLayout();
                }
            });
            valueAnimator.start();
        }
    };
}