o modify the badge under ios8 you have to ask for permissions
let settings = UIUserNotificationSettings(forTypes: UIUserNotificationType.Badge, categories: nil)
UIApplication.sharedApplication().registerUserNotificationSettings(settings)
or in objC
UIUserNotificationSettings *settings = [UIUserNotificationSettings settingsForTypes:UIUserNotificationTypeBadge categories:nil];
[[UIApplication sharedApplication] registerUserNotificationSettings:settings];
转 How to correctly set application badge value in iOS 8?
原文:http://www.cnblogs.com/liangjialun219/p/3972832.html