public void cancel() {
        mActivePointerId = INVALID_POINTER;
        clearMotionHistory();

        if (mVelocityTracker != null) {
            mVelocityTracker.recycle();
            mVelocityTracker = null;
        }
    }
The result of a call to this method is equivalent to
{@link #processTouchEvent(MotionEvent)} receiving an ACTION_CANCEL event.
app/src/main/java/home/smart/fly/animations/widget/slidepanel/ViewDragHelper.java