以编程方式将 UIScrollView 滚动到 Swift 中的子 UIView(子视图)的顶部

这是我最后写的一个扩展.

Usage:

从我的视图控制器self调用.scrollView是UIScrollView和self的一个出口.commentsHeader是其中的一个视图，靠近底部:

self.scrollView.scrollToView(self.commentsHeader, animated: true)

Code:

您只需要scrollToView个方法，但也需要scrollToBottom/scrollToTop个方法，因为您可能也需要这些方法，但可以随意删除它们.

extension UIScrollView {

    // Scroll to a specific view so that it's top is at the top our scrollview
    func scrollToView(view:UIView, animated: Bool) {
        if let origin = view.superview {
            // Get the Y position of your child view
            let childStartPoint = origin.convertPoint(view.frame.origin, toView: self)
            // Scroll to a rectangle starting at the Y of your subview, with a height of the scrollview
            self.scrollRectToVisible(CGRect(x:0, y:childStartPoint.y,width: 1,height: self.frame.height), animated: animated)
        }
    }

    // Bonus: Scroll to top
    func scrollToTop(animated: Bool) {
        let topOffset = CGPoint(x: 0, y: -contentInset.top)
        setContentOffset(topOffset, animated: animated)
    }

    // Bonus: Scroll to bottom
    func scrollToBottom() {
        let bottomOffset = CGPoint(x: 0, y: contentSize.height - bounds.size.height + contentInset.bottom)
        if(bottomOffset.y > 0) {
            setContentOffset(bottomOffset, animated: true)
        }
    }

}