UIScrollViewDelegate——scrollviewdidenddrag中的animateWithDuration并没有像预期的那样工作

I have a UIScrollView with 2 sub views/pages side by side (horizontal content size = 2 * Screen Width + gutter space between pages). I would like to increase the completion speed of the animation, ie after the user has completed the dragging and lifted the finger. Based on the suggestions found in SO, I implemented a with 2 sub views/pages si