private void OnListenerUpdate(bool hasBeenChecked)
 {
     if (OnCheckStateChangeListener != null)
     {
         OnCheckStateChangeListener.CheckedChanged(this, hasBeenChecked);
     }
 }
        public void Init(Activity activity)
        {
            this.activity = activity;

            this.Click += (s, e) =>
            {
                if (!IsChecked)
                {
                    IsChecked = true;
                    ShowAnim();
                }
                else
                {
                    IsChecked = false;
                    Cancel();
                }

                if (OnCheckStateChangeListener != null)
                {
                    OnCheckStateChangeListener.CheckedChanged(this, IsChecked);
                }
            };
        }