如何从scrollView拖动到superview然后返回滚动

Question

我试图将包含众多自动生成按钮的ScrollView拖动到主视图上。

以下代码可以满足我的需求（我可能仍然可以清理一下）， 除了拖动完成后，我希望它能够快速回到滚动条上的原始位置。

下面的代码将替换相同位置的按钮，但基本上位于整个视图的顶部，而不是滚动条上。

有什么建议可以在返回时将其返回到子视图吗？

感谢您的帮助！ 约翰

    @IBAction func handleScrollPan(recognizer:UIPanGestureRecognizer) {

        if recognizer.state == UIGestureRecognizerState.began {
            scrollView.superview?.addSubview(recognizer.view!)
            let currentPoint = CGPoint(x:recognizer.view!.center.x, y:recognizer.view!.center.y)
            let newPoint = scrollView.convert(currentPoint, to: self.view)
            let translation = recognizer.translation(in: self.view)
            if let view = recognizer.view {
                view.center = CGPoint(x:newPoint.x + translation.x,
                                      y:newPoint.y + translation.y)
            }
            recognizer.setTranslation(CGPoint(x:0, y:0), in: self.view)
            firstLocation = CGPoint(x:scrollView.center.x, y:scrollView.center.y)

        } else if (recognizer.state == UIGestureRecognizerState.ended) {
            UIView.animate(withDuration: 0,
                       delay: 0,
                       options: UIViewAnimationOptions.curveEaseIn,
                       animations: {recognizer.view!.center = firstLocation},
                       completion: nil)

        } else {
            scrollView.superview?.addSubview(recognizer.view!)
            let currentPoint = CGPoint(x:recognizer.view!.center.x, y:recognizer.view!.center.y)
            let translation = recognizer.translation(in: self.view)
            if let view = recognizer.view {
                view.center = CGPoint(x:view.center.x + translation.x,
                              y:view.center.y + translation.y)
            }
            recognizer.setTranslation(CGPoint(x:0, y:0), in: self.view)
    }
}