public void tryToScrollTo(int to, int duration) {
            if (mPtrIndicator.isAlreadyHere(to)) {
                return;
            }
            mStart = mPtrIndicator.getCurrentPosY();
            mTo = to;
            int distance = to - mStart;
            if (DEBUG) {
                PtrCLog.d(LOG_TAG, "tryToScrollTo: start: %s, distance:%s, to:%s", mStart, distance, to);
            }
            removeCallbacks(this);

            mLastFlingY = 0;

            // fix #47: Scroller should be reused, https://github.com/liaohuqiu/android-Ultra-Pull-To-Refresh/issues/47
            if (!mScroller.isFinished()) {
                mScroller.forceFinished(true);
            }
            mScroller.startScroll(0, 0, 0, distance, duration);
            post(this);
            mIsRunning = true;
        }
The duration to close time

@param duration
ptr-lib/src/in/srain/cube/views/ptr/PtrFrameLayout.java