我是新手，我想取消出现的警报
新警报出现时的屏幕。
我试过了：
func showDefaultAlert(controller: UIViewController, title: String, message: String) {
// create the alert
let alert = UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.Alert)
// add an action (button)
alert.addAction(UIAlertAction(title: defaultTextForNormalAlertButton, style: UIAlertActionStyle.Default, handler: nil))
// show the alert
//controller.presentViewController(alert, animated: true, completion: nil)
self.showAlert(controller, alert: alert)
}
func showAlert(controller: UIViewController, alert: UIAlertController) {
if let currentPresentedViewController = UIApplication.sharedApplication().keyWindow?.rootViewController?.presentedViewController {
if currentPresentedViewController.isKindOfClass(UIAlertController) {
currentPresentedViewController.dismissViewControllerAnimated(false, completion: {
controller.presentViewController(alert, animated: true, completion: nil)
})
}else {
controller.presentViewController(alert, animated: true, completion: nil)
}
}
}
}
// Call to above method in view controller class:
SPSwiftAlert.sharedObject.showDefaultAlert(self, title:"Title1", message1: "Message")
SPSwiftAlert.sharedObject.showDefaultAlert(self, title:"Title2", message: "Message2")
--
但是上面的代码给出了运行时错误为：
Attempting to load the view of a view controller while it is deallocating is not allowed and may result in undefined behavior (<UIAlertController: 0x7fceb95dcfb0>)
最佳答案
显示UIAlertController后，您可以检查其可见性，如下所示：
出示UIAlertController：
let alerts=UIAlertController(title: "Test", message: "Test", preferredStyle: .Alert)
presentViewController(alerts, animated: true, completion: nil)
检查
UIAlertController是否可见：if (alerts.isViewLoaded())
{
print("Visible")
//Here you can dismiss the controller
//dismissViewControllerAnimated(true, completion: nil)
}
查看此演示：Source code
关于ios - 在呈现新的UIAlertViewController之前关闭旧的UIAlertViewController，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/36933184/