我不知道如何在Spritekit中获得一个警报框。下面这段代码曾经有效,但是KeyWindow已经被废弃了,那么我现在该怎么做呢?
let currentViewController : UIViewController=UIApplication.shared.keyWindow!.rootViewController!
我已经尝试过。
let currentViewController : UIViewController = (self.view?.window!.rootViewController)!
其他的一些变体,但似乎都没用 警报就是不弹出。
谁能告诉我这个问题?
完整的代码块。
let ac = UIAlertController(title: "Connect to others", message: nil, preferredStyle: .actionSheet)
ac.addAction(UIAlertAction(title: "Host a session", style: .default, handler: startHosting))
ac.addAction(UIAlertAction(title: "Join a session", style: .default, handler: joinSession))
ac.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
let currentViewController :
UIViewController = (self.view?.window!.rootViewController)!
currentViewController.present(ac, animated: true, completion: nil)
这就可以了,虽然不知道为什么会这样,但是确实可以了。
添加DispatchQueue
DispatchQueue.main.async {
let ac = UIAlertController(title: "Connect to others", message: nil, preferredStyle: .actionSheet)
ac.addAction(UIAlertAction(title: "Host a session", style: .default, handler: self.startHosting))
ac.addAction(UIAlertAction(title: "Join a session", style: .default, handler: self.joinSession))
ac.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
self.view?.window?.rootViewController!.present(ac, animated: true, completion: nil)
}
let alert = UIAlertController(title: "Restore Purchases?", message: "Do you want to restore a purchase?", preferredStyle: .alert)
let ok = UIAlertAction(title: "OK", style: .default, handler: { action in
//run code here when ok button is pressed
})
alert.addAction(ok)
self.view?.window?.rootViewController?.present(alert, animated: true, completion: nil)
}