@Override
 public void onAnimationEnd(Animation animation) {
   if (mRefreshing) {
     // Make sure the progress view is fully visible
     mProgress.setAlpha(MAX_ALPHA);
     mProgress.start();
     if (mNotify) {
       if (mListener != null) {
         mListener.onRefresh();
       }
     }
   } else {
     mProgress.stop();
     mCircleView.setVisibility(View.GONE);
     setColorViewAlpha(MAX_ALPHA);
     // Return the circle to its start position
     if (mScale) {
       setAnimationProgress(0 /* animation complete and view is hidden */);
     } else {
       setTargetOffsetTopAndBottom(
           mOriginalOffsetTop - mCurrentTargetOffsetTop, true /* requires update */);
     }
   }
   mCurrentTargetOffsetTop = mCircleView.getTop();
 }
 private void createProgressView() {
   mCircleView = new CircleImageView(getContext(), CIRCLE_BG_LIGHT, CIRCLE_DIAMETER / 2);
   mProgress = new MaterialProgressDrawable(getContext(), this);
   mProgress.setBackgroundColor(CIRCLE_BG_LIGHT);
   mCircleView.setImageDrawable(mProgress);
   mCircleView.setVisibility(View.GONE);
   addView(mCircleView);
 }
 /**
  * The refresh indicator starting and resting position is always positioned near the top of the
  * refreshing content. This position is a consistent location, but can be adjusted in either
  * direction based on whether or not there is a toolbar or actionbar present.
  *
  * @param scale Set to true if there is no view at a higher z-order than where the progress
  *     spinner is set to appear.
  * @param start The offset in pixels from the top of this view at which the progress spinner
  *     should appear.
  * @param end The offset in pixels from the top of this view at which the progress spinner should
  *     come to rest after a successful swipe gesture.
  */
 public void setProgressViewOffset(boolean scale, int start, int end) {
   mScale = scale;
   mCircleView.setVisibility(View.GONE);
   mOriginalOffsetTop = mCurrentTargetOffsetTop = start;
   mSpinnerFinalOffset = end;
   mUsingCustomStart = true;
   mCircleView.invalidate();
 }
  private void moveSpinner(float overscrollTop) {
    mProgress.showArrow(true);
    float originalDragPercent = overscrollTop / mTotalDragDistance;

    float dragPercent = Math.min(1f, Math.abs(originalDragPercent));
    float adjustedPercent = (float) Math.max(dragPercent - .4, 0) * 5 / 3;
    float extraOS = Math.abs(overscrollTop) - mTotalDragDistance;
    float slingshotDist =
        mUsingCustomStart ? mSpinnerFinalOffset - mOriginalOffsetTop : mSpinnerFinalOffset;
    float tensionSlingshotPercent =
        Math.max(0, Math.min(extraOS, slingshotDist * 2) / slingshotDist);
    float tensionPercent =
        (float) ((tensionSlingshotPercent / 4) - Math.pow((tensionSlingshotPercent / 4), 2)) * 2f;
    float extraMove = (slingshotDist) * tensionPercent * 2;

    int targetY = mOriginalOffsetTop + (int) ((slingshotDist * dragPercent) + extraMove);
    // where 1.0f is a full circle
    if (mCircleView.getVisibility() != View.VISIBLE) {
      mCircleView.setVisibility(View.VISIBLE);
    }
    if (!mScale) {
      ViewCompat.setScaleX(mCircleView, 1f);
      ViewCompat.setScaleY(mCircleView, 1f);
    }
    if (overscrollTop < mTotalDragDistance) {
      if (mScale) {
        setAnimationProgress(overscrollTop / mTotalDragDistance);
      }
      if (mProgress.getAlpha() > STARTING_PROGRESS_ALPHA
          && !isAnimationRunning(mAlphaStartAnimation)) {
        // Animate the alpha
        startProgressAlphaStartAnimation();
      }
      float strokeStart = adjustedPercent * .8f;
      mProgress.setStartEndTrim(0f, Math.min(MAX_PROGRESS_ANGLE, strokeStart));
      mProgress.setArrowScale(Math.min(1f, adjustedPercent));
    } else {
      if (mProgress.getAlpha() < MAX_ALPHA && !isAnimationRunning(mAlphaMaxAnimation)) {
        // Animate the alpha
        startProgressAlphaMaxAnimation();
      }
    }
    float rotation = (-0.25f + .4f * adjustedPercent + tensionPercent * 2) * .5f;
    mProgress.setProgressRotation(rotation);
    setTargetOffsetTopAndBottom(targetY - mCurrentTargetOffsetTop, true /* requires update */);
  }
 private void startScaleUpAnimation(AnimationListener listener) {
   mCircleView.setVisibility(View.VISIBLE);
   if (android.os.Build.VERSION.SDK_INT >= 11) {
     // Pre API 11, alpha is used in place of scale up to show the
     // progress circle appearing.
     // Don't adjust the alpha during appearance otherwise.
     mProgress.setAlpha(MAX_ALPHA);
   }
   mScaleAnimation =
       new Animation() {
         @Override
         public void applyTransformation(float interpolatedTime, Transformation t) {
           setAnimationProgress(interpolatedTime);
         }
       };
   mScaleAnimation.setDuration(mMediumAnimationDuration);
   if (listener != null) {
     mCircleView.setAnimationListener(listener);
   }
   mCircleView.clearAnimation();
   mCircleView.startAnimation(mScaleAnimation);
 }