在我的项目中,我使用rootViewController?.dismiss将一些视图控制器关闭回主VC。
在完成处理程序中,我想在主视图控制器再次可见时呈现UIAlertController。
我的问题是UIAlertController永远不会出现。我的预感是因为我在launchFrom参数中使用self。我是否需要获得对主VC的引用,并将其呈现在那里?
解散VC并尝试提示警报:
self.view.window!.rootViewController?.dismiss(animated: false, completion: {
Constants.presentThankYou(launchFrom: self)
})
presentThankYou方法
static func presentThankYou(launchFrom: UIViewController) {
let alertController = UIAlertController(title: "Thank You!", message: "You did it!", preferredStyle: UIAlertControllerStyle.alert)
let okAction = UIAlertAction(title: "Close", style: UIAlertActionStyle.default) { (result : UIAlertAction) -> Void in
print("Done")
}
alertController.addAction(okAction)
launchFrom.present(alertController, animated: true, completion: nil)
}
在我的所有VC被解雇后,如何呈现警报控制器?
在我的脑海中,尝试在viewDidAppear
做。要防止警报一直显示,请使用bool shouldShowThankYouAlert
并在dismiss
completion
处理程序中将此值设置为true
如果需要,你也可以参考这个,只需调用警报显示在被解雇的Controller的viewWillDisappear中
override func viewWillDisappear(_ animated: Bool) {
if self.isMovingFromParentViewController {
DispatchQueue.main.async {
wrapperClass.BasicAlert("View is Dismissed", message: "", view: self)
}
}
}
当视图被完全关闭时,这将显示警报
我没有检查,但如何使用窗口而不是UIViewController。
self.view.window!.rootViewController?.dismiss(animated: false, completion: {
Constants.presentThankYou()
})
static func presentThankYou() {
let alertController = UIAlertController(title: "Thank You!", message: "You did it!", preferredStyle: UIAlertControllerStyle.alert)
let okAction = UIAlertAction(title: "Close", style: UIAlertActionStyle.default) { (result : UIAlertAction) -> Void in
print("Done")
}
alertController.addAction(okAction)
appDelegate.window.present(alertController, animated: true, completion: nil)
}
所以一个问题是,完成块不需要主线程。我建议强制完成执行一些代码。
var topController: UIViewController? {
if var temp = UIApplication.shared.keyWindow?.rootViewController {
while let presentedViewController = temp.presentedViewController {
temp = presentedViewController
}
return temp
}
return nil
}
self.view.window!.rootViewController?.dismiss(animated: false, completion: {
DispatchQueue.main.async {
guard let top = topController else { return }
Constants.presentThankYou(launchFrom: top)
}
})