我知道之前已经有人问过这个问题，但是我想弄清楚我的项目存在的问题，因为标题（a）试图在（a）上提出，我已经检查了所有segue触发器，看看是否意外设置了segue转到已经打开的同一个视图控制器，但事实并非如此。
查看控制器1代码
import UIKit
import UserNotifications
class NotificationViewController: UIViewController {
let isRegisteredForRemoteNotifications = UIApplication.shared.isRegisteredForRemoteNotifications
let current = UNUserNotificationCenter.current()
@IBAction func Notification(_ sender: Any) {
UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound, .badge], completionHandler: {didAllow, error in})
var i = 0
while i < 1{
current.getNotificationSettings(completionHandler: { (settings) in
if settings.authorizationStatus == .notDetermined {
// Notification permission has not been asked yet, go for it!
}
if settings.authorizationStatus == .denied {
i = i + 1
DispatchQueue.main.async {
self.performSegue(withIdentifier: "ToLocation", sender: self)
// Notification permission was previously denied, go to settings & privacy to re-enable
}
}
if settings.authorizationStatus == .authorized {
i = i + 1
DispatchQueue.main.async {
self.performSegue(withIdentifier: "ToLocation", sender: self)
// Notification permission was already granted
}
}
})
}
}
override func viewDidLoad() {
current.getNotificationSettings(completionHandler: { (settings) in
if settings.authorizationStatus == .notDetermined {
// Notification permission has not been asked yet, go for it!
}
if settings.authorizationStatus == .denied {
DispatchQueue.main.async {
self.performSegue(withIdentifier: "ToLocation", sender: self)
// Notification permission was previously denied, go to settings & privacy to re-enable
}
}
if settings.authorizationStatus == .authorized {
DispatchQueue.main.async {
self.performSegue(withIdentifier: "ToLocation", sender: self)
// Notification permission was already granted
}
}
})
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
查看控制器2代码
import UIKit
import CoreLocation
class LocationViewController: UIViewController {
@IBOutlet weak var textview: UITextView!
let locationManager = CLLocationManager()
@IBAction func OnLocation(_ sender: Any) {
locationManager.delegate = self as? CLLocationManagerDelegate
var i = 0
while i < 1{
switch CLLocationManager.authorizationStatus() {
case .notDetermined:
// Request when-in-use authorization initially
locationManager.requestWhenInUseAuthorization()
break
case .restricted, .denied:
i = i + 1
DispatchQueue.main.async {
self.performSegue(withIdentifier: "ToLogin", sender: self)
}
// Disable location features
//disableMyLocationBasedFeatures()
break
case .authorizedWhenInUse:
i = i + 1
DispatchQueue.main.async {
self.performSegue(withIdentifier: "ToLogin", sender: self)
}
// Enable basic location features
//enableMyWhenInUseFeatures()
break
case .authorizedAlways:
// Enable any of your app's location features
// enableMyAlwaysFeatures()
break
}
}
}
override func viewDidLoad() {
func locationManager(_ manager: CLLocationManager,
didChangeAuthorization status: CLAuthorizationStatus) { switch status {
case .restricted, .denied:
self.performSegue(withIdentifier: "ToLogin", sender: self)
break
case .authorizedWhenInUse:
self.performSegue(withIdentifier: "ToLogin", sender: self)
break
case .authorizedAlways:
self.performSegue(withIdentifier: "ToLogin", sender: self)
break
case .notDetermined:
break
}
}
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
错误信息
018-02-27 23：06：41.534749 + 1030请求[27358：1351259]警告：尝试
呈现
在演讲时
正在处理！
最佳答案
不不不不不是这样的抱歉，UNUserNotification的requestAuthorization方法的completeHandler结果参数可能在后台线程上执行。
此功能的提示
@IBAction func Notification(_ sender: Any)
*应以小写字母开头
*提供一个名称，该名称可以推断出它完成的动作
*更改发送者的类型（如果知道的话），这样就可以显式调用该对象的属性或方法而无需强制转换。
在函数范围内继续执行其余代码。 requestAuthorization对此负有唯一责任-请求权限-响应为didAllow或错误。您从不检查它，并继续启动另一个响应也是另一个线程的块
最重要的是：您的调用requestAuthorization和getNotificationSettings在一个循环内（为什么？），如果此代码在30％的时间内执行，您会很幸运。
因此，您应该分离一些涉及权限的代码，阅读有关GRASP原理的几行内容，还阅读每一章here