ios - 如何在 Collection View 的底部/页脚中添加 uiactivity 指示器？
<p><p>我是 swift 新手。我不知道我该怎么做。基本上我需要在 Collection View 加载所有数据时显示 uiactivity 指示器，然后您尝试滚动然后显示 uiactivity 指示器。这意味着从网络加载更多数据，请稍等。</p>
<p>我做了什么。 </p>
<pre><code> ///define
var indicatorFooter : UIActivityIndicatorView!
//set upUIActivityIndicatorView to the collection view
override func setupViews() {
indicatorFooter = UIActivityIndicatorView(frame: CGRect(x: CGFloat(0), y: CGFloat(0), width: CGFloat(collectionView.frame.width), height: CGFloat(44)))
indicatorFooter.color = UIColor.black
collectionView.addSubview(indicatorFooter)
}
//end of the scroll view then load next 20 data from api
func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {
// UITableView only moves in one direction, y axis
let currentOffset = scrollView.contentOffset.y
let maximumOffset = scrollView.contentSize.height - scrollView.frame.size.height
// Change 10.0 to adjust the distance from bottom
if maximumOffset - currentOffset <= 10.0 {
self.loadMore()
}
}
//request web to down load data
func loadMore(){
//but it is not workingindicator
indicatorFooter.startAnimating()
}
</code></pre></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>将以下 <code>extension</code> 添加到您的代码中:</p>
<pre><code>extension UIView {
// MARK: Activity Indicator
func activityIndicator(show: Bool) {
activityIndicator(show: show, style: .gray)
}
func activityIndicator(show: Bool, style: UIActivityIndicatorViewStyle) {
var spinner: UIActivityIndicatorView? = viewWithTag(NSIntegerMax - 1) as? UIActivityIndicatorView
if spinner != nil {
spinner?.removeFromSuperview()
spinner = nil
}
if spinner == nil && show {
spinner = UIActivityIndicatorView.init(activityIndicatorStyle: style)
spinner?.translatesAutoresizingMaskIntoConstraints = false
spinner?.hidesWhenStopped = true
spinner?.tag = NSIntegerMax - 1
if Thread.isMainThread {
spinner?.startAnimating()
} else {
DispatchQueue.main.async {
spinner?.startAnimating()
}
}
insertSubview((spinner)!, at: 0)
NSLayoutConstraint.init(item: spinner!, attribute: .centerX, relatedBy: .equal, toItem: self, attribute: .centerX, multiplier: 1.0, constant: 0.0).isActive = true
NSLayoutConstraint.init(item: spinner!, attribute: .centerY, relatedBy: .equal, toItem: self, attribute: .centerY, multiplier: 1.0, constant: 0.0).isActive = true
spinner?.isHidden = !show
}
}
}
</code></pre>
<p>要将微调器添加到您的 <code>collectionView</code>，您只需调用:</p>
<pre><code>collectionView.activityIndicator(show: true)
</code></pre></p>
<p style="font-size: 20px;">关于ios - 如何在 Collection View 的底部/页脚中添加 uiactivity 指示器？，我们在Stack Overflow上找到一个类似的问题：
<a href="https://stackoverflow.com/questions/44782527/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/44782527/
</a>
</p>
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