ios - 在 Swift 中添加和删除 View 覆盖

Question

根据这个问题:Loading Screen from any Class in Swift

问题:当调用 hideOverlayView() 时，加载覆盖 View 会显示但不会隐藏。然而奇怪的是，覆盖层会在一段时间后消失(出现后 15 到 30 秒)

代码:包含在FirstController.swift

public class LoadingOverlay{

var overlayView = UIView()
var activityIndicator = UIActivityIndicatorView()

class var shared: LoadingOverlay {
    struct Static {
        static let instance: LoadingOverlay = LoadingOverlay()
    }
    return Static.instance
}

public func showOverlay() {
    if  let appDelegate = UIApplication.sharedApplication().delegate as? AppDelegate,
        let window = appDelegate.window {
            overlayView.frame = CGRectMake(0, 0, 80, 80)
            overlayView.center = CGPointMake(window.frame.width / 2.0, window.frame.height / 2.0)
            overlayView.backgroundColor = MyGlobalVariables.UICOLORGREEN
            overlayView.clipsToBounds = true
            overlayView.layer.cornerRadius = 10

            activityIndicator.frame = CGRectMake(0, 0, 40, 40)
            activityIndicator.activityIndicatorViewStyle = .WhiteLarge
            activityIndicator.center = CGPointMake(overlayView.bounds.width / 2, overlayView.bounds.height / 2)

            overlayView.addSubview(activityIndicator)
            window.addSubview(overlayView)

            activityIndicator.startAnimating()
    }
}

public func hideOverlayView() {
    activityIndicator.stopAnimating()
    overlayView.removeFromSuperview()
}
}

并在 DataManager.swift 中调用函数:

LoadingOverlay.shared.showOverlay()

解决方案:

我正在调用后台线程。根据以下答案，调用为:

dispatch_async(dispatch_get_main_queue(), { // This makes the code run on the main thread
  LoadingOverlay.shared.hideOverlayView()          
})

Answer 1

swift 2

您是从后台线程调用 hideOverlayView() 吗？如果是，则应确保它在主线程上运行:

dispatch_async(dispatch_get_main_queue(), { // This makes the code run on the main thread
  LoadingOverlay.shared.hideOverlayView()          
})

swift 3+

DispatchQueue.main.async {
  LoadingOverlay.shared.hideOverlayView()
}