[IOS]如何把loading控件放在屏幕中央(UIActivityIndicatorView)

参考:https://stackoverflow.com/questions/8090579/how-to-display-activity-indicator-in-middle-of-the-iphone-screen/8090599

旧的方式,只需要把UIActivityIndicatorView拉到storyboard上面,然后给它配置全屏的view的约束就可以了.

但是新的Safe Area模式不能把约束加在全屏的view上面,这就尴尬了.只能代码手动配置出来了

let activityIndicator = UIActivityIndicatorView(style:UIActivityIndicatorView.Style.whiteLarge)


activityIndicator.center = self.view.center
activityIndicator.startAnimating()
self.view.addSubview(activityIndicator)