ExpandUtils

import android.view.View;
import android.view.ViewGroup.LayoutParams;

import com.nineoldandroids.animation.Animator;
import com.nineoldandroids.animation.AnimatorListenerAdapter;
import com.nineoldandroids.animation.ValueAnimator;

public class ExpandUtils
{
    public interface IOnAnimatorFinished
    {
        public void onAnimatorFinished();
    }

    public static void expand(final View v, final IOnAnimatorFinished animatorFinishedListener, Integer durationInMs)
    {
        v.measure(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);

        final int startHeight = 0;
        final int targetHeight = v.getMeasuredHeight();

        v.getLayoutParams().height = startHeight;
        v.setVisibility(View.VISIBLE);

        ValueAnimator animation = ValueAnimator.ofInt(startHeight, targetHeight);
        animation.addUpdateListener(new ValueAnimator.AnimatorUpdateListener()
        {
            @Override
            public void onAnimationUpdate(ValueAnimator valueAnimator)
            {
                v.getLayoutParams().height = (Integer) valueAnimator.getAnimatedValue();
                v.requestLayout();
            }
        });
        animation.addListener(new AnimatorListenerAdapter()
        {
            @Override
            public void onAnimationEnd(Animator animation)
            {
                v.getLayoutParams().height = LayoutParams.WRAP_CONTENT;
                if (animatorFinishedListener != null)
                    animatorFinishedListener.onAnimatorFinished();
            }
        });
        // 1dp/ms
        animation.setDuration(durationInMs != null ? durationInMs : (int) (targetHeight / v.getContext().getResources().getDisplayMetrics().density));
        animation.start();
    }

    public static void collapse(final View v, final IOnAnimatorFinished animatorFinishedListener, Integer durationInMs)
    {
        final int startHeight = v.getMeasuredHeight();
        final int targetHeight = 0;

        ValueAnimator animation = ValueAnimator.ofInt(startHeight, targetHeight);
        animation.addUpdateListener(new ValueAnimator.AnimatorUpdateListener()
        {
            @Override
            public void onAnimationUpdate(ValueAnimator valueAnimator)
            {
                v.getLayoutParams().height = (Integer) valueAnimator.getAnimatedValue();
                v.requestLayout();
            }
        });
        animation.addListener(new AnimatorListenerAdapter()
        {
            @Override
            public void onAnimationEnd(Animator animation)
            {
                v.setVisibility(View.GONE);
                if (animatorFinishedListener != null)
                    animatorFinishedListener.onAnimatorFinished();
            }
        });

        // 1dp/ms
        animation.setDuration(durationInMs != null ? durationInMs : (int) (startHeight / v.getContext().getResources().getDisplayMetrics().density));
        animation.start();
    }
}