Swift实现修改UITableView，UIScrollView滚动条颜色
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参考技术A 亲测好使哈~~~https://www.meiwen.com.cn/subject/onwkjqtx.html
https://stackoverflow.com/questions/12005187/ios-changing-uiscrollview-scrollbar-color-to-different-colors/28718210#28718210
Swift 3：有弹性的 UITableView 页脚
【中文标题】Swift 3：有弹性的 UITableView 页脚【英文标题】：Swift 3: Stretchy UITableView footer 【发布时间】：2017-04-03 17:19:46 【问题描述】：谁能告诉我如何实现一个有弹性的 UITableView 页脚。
我希望我的页脚中的图像在用户“过度滚动”时拉伸/增加大小。 （如果用户在 UITableView 已经在底部时向下滚动）
当前代码：
private let tableFooterHeight: CGFloat = 300
private var footerCustomView = UIImageView()
func setupFooterView()
// Footer view
self.footerCustomView = UIImageView(frame: CGRect.zero)
self.footerCustomView.backgroundColor = UIColor.brown
self.footerCustomView.image = UIImage(named: "image")
self.view.addSubview(self.footerCustomView)
// self.view.bringSubview(toFront: self.tableView)
self.tableView.contentInset = UIEdgeInsets(top: 0, left: 0, bottom: self.tableFooterHeight, right: 0)
self.footerCustomView.translatesAutoresizingMaskIntoConstraints = false
let leadingConstraint = NSLayoutConstraint(item: self.footerCustomView,
attribute: .leading,
relatedBy: .equal,
toItem: self.tableView,
attribute: .leading,
multiplier: 1,
constant: 0)
let trailingConstraint = NSLayoutConstraint(item: self.footerCustomView,
attribute: .trailing,
relatedBy: .equal,
toItem: self.tableView,
attribute: .trailing,
multiplier: 1,
constant: 0)
let bottomConstraint = NSLayoutConstraint(item: self.footerCustomView,
attribute: .bottom,
relatedBy: .equal,
toItem: self.tableView,
attribute: .bottom,
multiplier: 1,
constant: 0)
let heightConstraint = NSLayoutConstraint(item: self.footerCustomView,
attribute: .height,
relatedBy: .equal,
toItem: nil,
attribute: .height,
multiplier: 1,
constant: self.tableFooterHeight)
self.view.addConstraints([bottomConstraint, trailingConstraint, heightConstraint, leadingConstraint])
func scrollViewDidScroll(_ scrollView: UIScrollView)
self.updateFooterView()
func updateFooterView()
if self.tableView.bounds.origin.y > 1559 // 1559 is end of tableView
let diff = self.tableView.contentOffset.y - 1559
self.footerCustomView.frame.size.height = self.tableFooterHeight + diff
谢谢！
正常：
拉伸模式：
【问题讨论】：
您应该将底部的 contentInset 添加到表格视图中，并在表格视图的超级视图底部添加一个图像视图。确保它被添加到表格视图的后面。并在滚动视图委托中，scrollViewDidScroll，调整图像视图框架的过度滚动量。 感谢您的意见！我在上面的问题中更新了我的代码。 tableFooterView 正在向下增长。我试图在 tableviews 底部和 footerCustomView 之间添加底部约束，但没有运气。此外，当我调用 self.view.bringSubview(toFront: self.tableView) 时，我的 customView 不可见，并且被我最后一个单元格背景颜色覆盖。您有什么想法吗？我是否按照您的描述实现了代码？ 【参考方案1】：一个 UITableView 已经有一个属性 tableFooterView
我们可以用一个 UIImageView、一个 UIScrollView 和另一个 UIView 子类化 UIView 来作为 UIImageView 的容器。我们称之为 StretchyFooterView。
我喜欢使用名为 PureLayout 的库来添加约束。
class YourView: UIView, UITableViewDelegate
fileprivate let tableView = UITableView(frame: .zero, style: .plain)
fileprivate let image = UIImage(named: "yourImage")!
// ----------------------------------------------------------------------------
// MARK: Init
// ----------------------------------------------------------------------------
override init(frame: CGRect)
super.init(frame: frame)
setupViews()
required init?(coder aDecoder: NSCoder)
fatalError("init(coder:) has not been implemented")
// ----------------------------------------------------------------------------
// MARK: UIView
// ----------------------------------------------------------------------------
override func updateConstraints()
tableView.autoPinEdgesToSuperviewEdges()
super.updateConstraints()
override func layoutSubviews()
super.layoutSubviews()
// do this after the view lays out so we know the frame width and height
let imageAspect = image.size.width / image.size.height
let footerWidth = frame.size.width
let footerHeight = footerWidth / imageAspect
let footerSize = CGSize(width: footerWidth, height: footerHeight)
let footerFrame = CGRect(origin: .zero, size: footerSize)
tableView.tableFooterView = StretchyFooterView(frame: footerFrame, image: image)
// ----------------------------------------------------------------------------
// MARK: Internal
// ----------------------------------------------------------------------------
func scrollViewDidScroll(_ scrollView: UIScrollView)
let verticalScrollDistance = scrollView.contentOffset.y
let bottomOfView = frame.height
if let stretchyFooterView = tableView.tableFooterView as? StretchyFooterView
stretchyFooterView.stretchBy(verticalScrollDistance, bottomBound: bottomOfView)
// ----------------------------------------------------------------------------
// MARK: Private
// ----------------------------------------------------------------------------
fileprivate func setupViews()
tableView.delegate = self
addSubview(tableView)
class StretchyFooterView: UIView
fileprivate let containerView = UIView()
fileprivate let scrollView = UIScrollView()
fileprivate let imageView = UIImageView()
fileprivate let image: UIImage
// ----------------------------------------------------------------------------
// MARK: Init
// ----------------------------------------------------------------------------
init(frame: CGRect, image: UIImage)
self.image = image
super.init(frame: frame)
setupViews()
required init?(coder aDecoder: NSCoder)
fatalError("init(coder:) has not been implemented")
// ----------------------------------------------------------------------------
// MARK: UIView
// ----------------------------------------------------------------------------
override func updateConstraints()
containerView.autoCenterInSuperview()
containerView.autoMatch(.height, to: .height, of: scrollView)
imageView.autoPinEdgesToSuperviewEdges()
imageView.autoMatch(.width, to: .height, of: scrollView, withMultiplier: image.aspect)
super.updateConstraints()
// ----------------------------------------------------------------------------
// MARK: Internal
// ----------------------------------------------------------------------------
func stretchBy(_ distanceScrolled: CGFloat, bottomBound: CGFloat)
let distanceFromTop = bottomBound + distanceScrolled // the footer could be offscreen, so we need to add the distance scrolled to the bottom of the view
let distanceFromBottom = frame.maxY - distanceFromTop // this is how much we need to scroll
if distanceFromBottom < 0 // once we hit zero and below, we need to stretch the height
let origin = CGPoint.zero // since we are scrolling, the origin needs to stay at zero
let newSize = CGSize(width: frame.width, height: frame.height - distanceFromBottom) // subtract distanceFromBottom because it's negative
scrollView.frame = CGRect(origin: origin, size: newSize)
// ----------------------------------------------------------------------------
// MARK: Private
// ----------------------------------------------------------------------------
fileprivate func setupViews()
imageView.image = image
containerView.addSubview(imageView)
scrollView.frame = bounds
scrollView.addSubview(containerView)
addSubview(scrollView)
【讨论】：
【参考方案2】：如果您使用 Storyboard，则为简单变体：
-
Add empty view as tableView footer。
Connect an outlet to tableView delegate。
实施 scrollViewDidScroll(_ scrollView: UIScrollView):
func scrollViewDidScroll(_ scrollView: UIScrollView)
guard scrollView == mainTableView else return
updateTableFooterFrame()
func updateTableFooterFrame()
let distanceFromTop = mainTableView.frame.height + mainTableView.contentOffset.y
var distanceScrolled = distanceFromTop - mainTableView.contentSize.height
distanceScrolled = distanceScrolled > 0 ? distanceScrolled : 0
let newFooterFrame = CGRect(
x: 0, y: mainTableView.contentSize.height,
width: mainTableView.frame.width,
height: distanceScrolled
)
tableFooterView.frame = newFooterFrame
【讨论】：
如果可能，请努力提供额外的解释，而不仅仅是代码。此类答案往往更有用，因为它们可以帮助社区成员，尤其是新开发人员更好地理解解决方案的推理，并有助于避免需要解决后续问题。以上是关于Swift实现修改UITableView，UIScrollView滚动条颜色的主要内容，如果未能解决你的问题，请参考以下文章
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