private void init() {
    setVerticalFadingEdgeEnabled(false);

    headerContainer =
        (LinearLayout) LayoutInflater.from(getContext()).inflate(R.layout.ptr_header, null);
    header = (RelativeLayout) headerContainer.findViewById(R.id.ptr_id_header);
    text = (TextView) header.findViewById(R.id.ptr_id_text);
    lastUpdatedTextView = (TextView) header.findViewById(R.id.ptr_id_last_updated);
    image = (ImageView) header.findViewById(R.id.ptr_id_image);
    spinner = (ProgressBar) header.findViewById(R.id.ptr_id_spinner);

    pullToRefreshText = getContext().getString(R.string.ptr_pull_to_refresh);
    releaseToRefreshText = getContext().getString(R.string.ptr_release_to_refresh);
    refreshingText = getContext().getString(R.string.ptr_refreshing);
    lastUpdatedText = getContext().getString(R.string.ptr_last_updated);

    flipAnimation =
        new RotateAnimation(
            0,
            -180,
            RotateAnimation.RELATIVE_TO_SELF,
            0.5f,
            RotateAnimation.RELATIVE_TO_SELF,
            0.5f);
    flipAnimation.setInterpolator(new LinearInterpolator());
    flipAnimation.setDuration(ROTATE_ARROW_ANIMATION_DURATION);
    flipAnimation.setFillAfter(true);

    reverseFlipAnimation =
        new RotateAnimation(
            -180,
            0,
            RotateAnimation.RELATIVE_TO_SELF,
            0.5f,
            RotateAnimation.RELATIVE_TO_SELF,
            0.5f);
    reverseFlipAnimation.setInterpolator(new LinearInterpolator());
    reverseFlipAnimation.setDuration(ROTATE_ARROW_ANIMATION_DURATION);
    reverseFlipAnimation.setFillAfter(true);

    addHeaderView(headerContainer);
    setState(State.PULL_TO_REFRESH);
    scrollbarEnabled = isVerticalScrollBarEnabled();

    ViewTreeObserver vto = header.getViewTreeObserver();
    vto.addOnGlobalLayoutListener(new PTROnGlobalLayoutListener());

    super.setOnItemClickListener(new PTROnItemClickListener());
    super.setOnItemLongClickListener(new PTROnItemLongClickListener());
  }
  @Override
  protected void onScrollChanged(int l, int t, int oldl, int oldt) {
    super.onScrollChanged(l, t, oldl, oldt);

    if (!hasResetHeader) {
      if (measuredHeaderHeight > 0 && state != State.REFRESHING) {
        setHeaderPadding(-measuredHeaderHeight);
      }

      hasResetHeader = true;
    }
  }