Expand - Collapse Animation JAVA

ExpandCollapse.java

public static void expand(final View v) {
        v.measure(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);
        final int targetHeight = v.getMeasuredHeight();

        // Older versions of android (pre API 21) cancel animations for views with a height of 0.
        v.getLayoutParams().height = 1;
        v.setVisibility(View.VISIBLE);
        Animation a = new Animation() {
            @Override
            protected void applyTransformation(float interpolatedTime, Transformation t) {
                v.getLayoutParams().height = interpolatedTime == 1
                        ? LinearLayout.LayoutParams.WRAP_CONTENT
                        : (int) (targetHeight * interpolatedTime);
                v.requestLayout();
            }

            @Override
            public boolean willChangeBounds() {
                return true;
            }
        };

        a.setDuration(300);
        //a.setDuration((int) (targetHeight / v.getContext().getResources().getDisplayMetrics().density));
        v.startAnimation(a);
}

public static void collapse(final View v) {
    final int initialHeight = v.getMeasuredHeight();
  
    Animation a = new Animation() {
        @Override
        protected void applyTransformation(float interpolatedTime, Transformation t) {
            if (interpolatedTime == 1) {
                v.setVisibility(View.GONE);
            } else {
                v.getLayoutParams().height = initialHeight - (int) (initialHeight * interpolatedTime);
                v.requestLayout();
            }
        }
  
        @Override
        public boolean willChangeBounds() {
            return true;
        }
    };
    a.setDuration(300);
    //a.setDuration((int) (targetHeight / v.getContext().getResources().getDisplayMetrics().density));
    v.startAnimation(a);
}