Android展开收起动画

public class AnimUtil {

    public static void expand(final View view) {
        view.measure(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
        final int viewHeight = view.getMeasuredHeight();
        view.getLayoutParams().height = 0;
        view.setVisibility(View.VISIBLE);

        Animation animation = new Animation() {
            @Override
            protected void applyTransformation(float interpolatedTime, Transformation t) {
                if (interpolatedTime == 1) {
                    view.getLayoutParams().height = ViewGroup.LayoutParams.WRAP_CONTENT;
                } else {
                    view.getLayoutParams().height = (int) (viewHeight * interpolatedTime);
                }
                view.requestLayout();
            }
        };
        animation.setDuration(300);
        animation.setInterpolator(new FastOutLinearInInterpolator());
        view.startAnimation(animation);
    }

    public static void collapse(final View view) {
        view.measure(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
        final int viewHeight = view.getMeasuredHeight();

        Animation animation = new Animation() {
            @Override
            protected void applyTransformation(float interpolatedTime, Transformation t) {
                if (interpolatedTime == 1) {
                    view.setVisibility(View.GONE);
                } else {
                    view.getLayoutParams().height = viewHeight - (int) (viewHeight * interpolatedTime);
                    view.requestLayout();
                }
            }
        };
        animation.setDuration(300);
        animation.setInterpolator(new FastOutLinearInInterpolator());
        view.startAnimation(animation);
    }
}