在registerUserNotificationSettings之后立即调用registerForRemoteNotifications？

Question

根据苹果的指南，它建议以这种方式注册通知：

- (void)applicationDidFinishLaunching:(UIApplication *)app {
   // other setup tasks here....

   // Register the supported interaction types.
    UIUserNotificationType types = UIUserNotificationTypeBadge |
                 UIUserNotificationTypeSound | UIUserNotificationTypeAlert;
    UIUserNotificationSettings *mySettings =
                [UIUserNotificationSettings settingsForTypes:types categories:nil];
    [[UIApplication sharedApplication] registerUserNotificationSettings:mySettings];

   // Register for remote notifications.
    [[UIApplication sharedApplication] registerForRemoteNotifications];
}

如上所示，它在

registerForRemoteNotifications

之后立即调用

registerUserNotificationSettings

，但是当应用程序第一次打开时，它不会成功获取访问令牌，因为用户尚未授予通知权限。

这样，应用程序在第二次打开时就会获得访问令牌。

苹果为什么这么建议？

我建议在

registerForRemoteNotifications

中调用

didRegisterUserNotificationSettings

，因为它会在用户授予通知权限后调用。

   func application(application: UIApplication, didRegisterUserNotificationSettings notificationSettings: UIUserNotificationSettings){


       application.registerForRemoteNotifications()

    }

我的建议正确吗？

Answer 1

您的建议是正确的。如果您想处理视图控制器中的失败，您可能总是想发布 NSNotification。

- (void)application:(UIApplication *)application didRegisterUserNotificationSettings:(UIUserNotificationSettings *)notificationSettings
{
if (notificationSettings.types != UIUserNotificationTypeNone) {
    //register to receive notifications
    [application registerForRemoteNotifications];
} else {
    // same as response to didFailToRegisterForRemoteNotificationsWithError
    NSDictionary* data = [NSDictionary dictionaryWithObject:@"" forKey:@"deviceToken"];
    [[NSNotificationCenter defaultCenter] postNotificationName:@"notificationsRegistered" object:self userInfo:data];
}    
}    

Answer 2

您还应该检查通知错误的情况。

 func application(application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: NSData) {
    print("Got token data! \(deviceToken)")
}

func application(application: UIApplication, didFailToRegisterForRemoteNotificationsWithError error: NSError) {
    print("Couldn't register: \(error)")
}

如果您想检查通知设置，请使用此方法：

func application(application: UIApplication, didRegisterUserNotificationSettings notificationSettings: UIUserNotificationSettings){

}

Answer 3

当我们请求用户允许从我们的应用程序发送通知时，代码如下：

UNUserNotificationCenter.current().requestAuthorization(
    options: [.alert, .badge, .sound]
) { (granted, error) in
    if granted {
        getNotificationSettings()
    }
}

使用此函数

getNotificationSettings()，在用户允许从我们的应用程序获取通知后立即调用registerForRemoteNotifications()：

func getNotificationSettings() {
  UNUserNotificationCenter.current().getNotificationSettings { settings in
    print("Notification settings: \(settings)")
    guard settings.authorizationStatus == .authorized else { return }
    DispatchQueue.main.async {
      UIApplication.shared.registerForRemoteNotifications()
      print("done with registerForRemoteNotifications()")
    }
  } 
}

来源：

https://www.kodeco.com/11395893-push-notifications-tutorial-getting-started?page=2（另请检查第一页）